Merge branch 'mouse-events' into project-panel-context-menu

crates/chat_panel/src/chat_panel.rs

@@ -75,9 +75,9 @@ impl ChatPanel {
             })
         });
 
-        let mut message_list = ListState::new(0, Orientation::Bottom, 1000., {
+        let mut message_list = ListState::new(0, Orientation::Bottom, 1000., cx, {
             let this = cx.weak_handle();
-            move |ix, cx| {
+            move |_, ix, cx| {
                 let this = this.upgrade(cx).unwrap().read(cx);
                 let message = this.active_channel.as_ref().unwrap().0.read(cx).message(ix);
                 this.render_message(message, cx)

crates/command_palette/src/command_palette.rs

@@ -1,9 +1,9 @@
 use fuzzy::{StringMatch, StringMatchCandidate};
 use gpui::{
     actions,
-    elements::{ChildView, Flex, Label, MouseState, ParentElement},
+    elements::{ChildView, Flex, Label, ParentElement},
     keymap::Keystroke,
-    Action, Element, Entity, MutableAppContext, View, ViewContext, ViewHandle,
+    Action, Element, Entity, MouseState, MutableAppContext, View, ViewContext, ViewHandle,
 };
 use picker::{Picker, PickerDelegate};
 use settings::Settings;
@@ -203,7 +203,7 @@ impl PickerDelegate for CommandPalette {
     fn render_match(
         &self,
         ix: usize,
-        mouse_state: &MouseState,
+        mouse_state: MouseState,
         selected: bool,
         cx: &gpui::AppContext,
     ) -> gpui::ElementBox {

crates/contacts_panel/src/contact_finder.rs

@@ -1,7 +1,7 @@
 use client::{ContactRequestStatus, User, UserStore};
 use gpui::{
-    actions, elements::*, Entity, ModelHandle, MutableAppContext, RenderContext, Task, View,
+    actions, elements::*, Entity, ModelHandle, MouseState, MutableAppContext, RenderContext, Task,
-    ViewContext, ViewHandle,
+    View, ViewContext, ViewHandle,
 };
 use picker::{Picker, PickerDelegate};
 use settings::Settings;
@@ -105,7 +105,7 @@ impl PickerDelegate for ContactFinder {
     fn render_match(
         &self,
         ix: usize,
-        mouse_state: &MouseState,
+        mouse_state: MouseState,
         selected: bool,
         cx: &gpui::AppContext,
     ) -> ElementBox {

crates/contacts_panel/src/contacts_panel.rs

@@ -12,8 +12,8 @@ use gpui::{
     geometry::{rect::RectF, vector::vec2f},
     impl_actions, impl_internal_actions,
     platform::CursorStyle,
-    AppContext, ClipboardItem, Element, ElementBox, Entity, LayoutContext, ModelHandle,
+    AppContext, ClipboardItem, Element, ElementBox, Entity, ModelHandle, MutableAppContext,
-    MutableAppContext, RenderContext, Subscription, View, ViewContext, ViewHandle, WeakViewHandle,
+    RenderContext, Subscription, View, ViewContext, ViewHandle, WeakViewHandle,
 };
 use join_project_notification::JoinProjectNotification;
 use menu::{Confirm, SelectNext, SelectPrev};
@@ -181,11 +181,8 @@ impl ContactsPanel {
         .detach();
 
         let mut this = Self {
-            list_state: ListState::new(0, Orientation::Top, 1000., {
+            list_state: ListState::new(0, Orientation::Top, 1000., cx, {
-                let this = cx.weak_handle();
+                move |this, ix, cx| {
-                move |ix, cx| {
-                    let this = this.upgrade(cx).unwrap();
-                    let this = this.read(cx);
                     let theme = cx.global::<Settings>().theme.clone();
                     let theme = &theme.contacts_panel;
                     let current_user_id =
@@ -255,11 +252,11 @@ impl ContactsPanel {
         theme: &theme::ContactsPanel,
         is_selected: bool,
         is_collapsed: bool,
-        cx: &mut LayoutContext,
+        cx: &mut RenderContext<Self>,
     ) -> ElementBox {
         enum Header {}
 
-        let header_style = theme.header_row.style_for(&Default::default(), is_selected);
+        let header_style = theme.header_row.style_for(Default::default(), is_selected);
         let text = match section {
             Section::Requests => "Requests",
             Section::Online => "Online",
@@ -331,11 +328,7 @@ impl ContactsPanel {
             .constrained()
             .with_height(theme.row_height)
             .contained()
-            .with_style(
+            .with_style(*theme.contact_row.style_for(Default::default(), is_selected))
-                *theme
-                    .contact_row
-                    .style_for(&Default::default(), is_selected),
-            )
             .boxed()
     }
 
@@ -346,7 +339,7 @@ impl ContactsPanel {
         theme: &theme::ContactsPanel,
         is_last_project: bool,
         is_selected: bool,
-        cx: &mut LayoutContext,
+        cx: &mut RenderContext<Self>,
     ) -> ElementBox {
         let project = &contact.projects[project_index];
         let project_id = project.id;
@@ -459,7 +452,7 @@ impl ContactsPanel {
         theme: &theme::ContactsPanel,
         is_incoming: bool,
         is_selected: bool,
-        cx: &mut LayoutContext,
+        cx: &mut RenderContext<ContactsPanel>,
     ) -> ElementBox {
         enum Decline {}
         enum Accept {}
@@ -558,11 +551,7 @@ impl ContactsPanel {
         row.constrained()
             .with_height(theme.row_height)
             .contained()
-            .with_style(
+            .with_style(*theme.contact_row.style_for(Default::default(), is_selected))
-                *theme
-                    .contact_row
-                    .style_for(&Default::default(), is_selected),
-            )
             .boxed()
     }
 

crates/context_menu/src/context_menu.rs

@@ -185,10 +185,9 @@ impl ContextMenu {
                     .with_children(self.items.iter().enumerate().map(|(ix, item)| {
                         match item {
                             ContextMenuItem::Item { label, .. } => {
-                                let style = style.item.style_for(
+                                let style = style
-                                    &Default::default(),
+                                    .item
-                                    Some(ix) == self.selected_index,
+                                    .style_for(Default::default(), Some(ix) == self.selected_index);
-                                );
                                 Label::new(label.to_string(), style.label.clone())
                                     .contained()
                                     .with_style(style.container)
@@ -210,10 +209,9 @@ impl ContextMenu {
                     .with_children(self.items.iter().enumerate().map(|(ix, item)| {
                         match item {
                             ContextMenuItem::Item { action, .. } => {
-                                let style = style.item.style_for(
+                                let style = style
-                                    &Default::default(),
+                                    .item
-                                    Some(ix) == self.selected_index,
+                                    .style_for(Default::default(), Some(ix) == self.selected_index);
-                                );
                                 KeystrokeLabel::new(
                                     action.boxed_clone(),
                                     style.keystroke.container,

crates/editor/src/editor.rs

@@ -592,11 +592,11 @@ impl ContextMenu {
         &self,
         cursor_position: DisplayPoint,
         style: EditorStyle,
-        cx: &AppContext,
+        cx: &mut RenderContext<Editor>,
     ) -> (DisplayPoint, ElementBox) {
         match self {
             ContextMenu::Completions(menu) => (cursor_position, menu.render(style, cx)),
-            ContextMenu::CodeActions(menu) => menu.render(cursor_position, style),
+            ContextMenu::CodeActions(menu) => menu.render(cursor_position, style, cx),
         }
     }
 }
@@ -633,14 +633,18 @@ impl CompletionsMenu {
         !self.matches.is_empty()
     }
 
-    fn render(&self, style: EditorStyle, _: &AppContext) -> ElementBox {
+    fn render(&self, style: EditorStyle, cx: &mut RenderContext<Editor>) -> ElementBox {
         enum CompletionTag {}
 
         let completions = self.completions.clone();
         let matches = self.matches.clone();
         let selected_item = self.selected_item;
         let container_style = style.autocomplete.container;
-        UniformList::new(self.list.clone(), matches.len(), move |range, items, cx| {
+        UniformList::new(
+            self.list.clone(),
+            matches.len(),
+            cx,
+            move |_, range, items, cx| {
                 let start_ix = range.start;
                 for (ix, mat) in matches[range].iter().enumerate() {
                     let completion = &completions[mat.candidate_id];
@@ -663,7 +667,10 @@ impl CompletionsMenu {
                                     .with_highlights(combine_syntax_and_fuzzy_match_highlights(
                                         &completion.label.text,
                                         style.text.color.into(),
-                                    styled_runs_for_code_label(&completion.label, &style.syntax),
+                                        styled_runs_for_code_label(
+                                            &completion.label,
+                                            &style.syntax,
+                                        ),
                                         &mat.positions,
                                     ))
                                     .contained()
@@ -680,7 +687,8 @@ impl CompletionsMenu {
                         .boxed(),
                     );
                 }
-        })
+            },
+        )
         .with_width_from_item(
             self.matches
                 .iter()
@@ -772,14 +780,18 @@ impl CodeActionsMenu {
         &self,
         mut cursor_position: DisplayPoint,
         style: EditorStyle,
+        cx: &mut RenderContext<Editor>,
     ) -> (DisplayPoint, ElementBox) {
         enum ActionTag {}
 
         let container_style = style.autocomplete.container;
         let actions = self.actions.clone();
         let selected_item = self.selected_item;
-        let element =
+        let element = UniformList::new(
-            UniformList::new(self.list.clone(), actions.len(), move |range, items, cx| {
+            self.list.clone(),
+            actions.len(),
+            cx,
+            move |_, range, items, cx| {
                 let start_ix = range.start;
                 for (ix, action) in actions[range].iter().enumerate() {
                     let item_ix = start_ix + ix;
@@ -808,7 +820,8 @@ impl CodeActionsMenu {
                         .boxed(),
                     );
                 }
-            })
+            },
+        )
         .with_width_from_item(
             self.actions
                 .iter()
@@ -2578,7 +2591,7 @@ impl Editor {
     pub fn render_code_actions_indicator(
         &self,
         style: &EditorStyle,
-        cx: &mut ViewContext<Self>,
+        cx: &mut RenderContext<Self>,
     ) -> Option<ElementBox> {
         if self.available_code_actions.is_some() {
             enum Tag {}
@@ -2612,7 +2625,7 @@ impl Editor {
         &self,
         cursor_position: DisplayPoint,
         style: EditorStyle,
-        cx: &AppContext,
+        cx: &mut RenderContext<Editor>,
     ) -> Option<(DisplayPoint, ElementBox)> {
         self.context_menu
             .as_ref()

crates/editor/src/element.rs

@@ -18,8 +18,9 @@ use gpui::{
     json::{self, ToJson},
     platform::CursorStyle,
     text_layout::{self, Line, RunStyle, TextLayoutCache},
-    AppContext, Axis, Border, Element, ElementBox, Event, EventContext, LayoutContext,
+    AppContext, Axis, Border, CursorRegion, Element, ElementBox, Event, EventContext,
-    MutableAppContext, PaintContext, Quad, Scene, SizeConstraint, ViewContext, WeakViewHandle,
+    LayoutContext, MutableAppContext, PaintContext, Quad, Scene, SizeConstraint, ViewContext,
+    WeakViewHandle,
 };
 use json::json;
 use language::{Bias, DiagnosticSeverity};
@@ -330,7 +331,10 @@ impl EditorElement {
         let content_origin = bounds.origin() + vec2f(layout.gutter_margin, 0.);
 
         cx.scene.push_layer(Some(bounds));
-        cx.scene.push_cursor_style(bounds, CursorStyle::IBeam);
+        cx.scene.push_cursor_region(CursorRegion {
+            bounds,
+            style: CursorStyle::IBeam,
+        });
 
         for (range, color) in &layout.highlighted_ranges {
             self.paint_highlighted_range(
@@ -1020,8 +1024,6 @@ impl Element for EditorElement {
             max_row.saturating_sub(1) as f32,
         );
 
-        let mut context_menu = None;
-        let mut code_actions_indicator = None;
         self.update_view(cx.app, |view, cx| {
             let clamped = view.clamp_scroll_left(scroll_max.x());
             let autoscrolled;
@@ -1041,7 +1043,11 @@ impl Element for EditorElement {
             if clamped || autoscrolled {
                 snapshot = view.snapshot(cx);
             }
+        });
 
+        let mut context_menu = None;
+        let mut code_actions_indicator = None;
+        cx.render(&self.view.upgrade(cx).unwrap(), |view, cx| {
             let newest_selection_head = view
                 .selections
                 .newest::<usize>(cx)

crates/file_finder/src/file_finder.rs

@@ -1,7 +1,7 @@
 use fuzzy::PathMatch;
 use gpui::{
-    actions, elements::*, AppContext, Entity, ModelHandle, MutableAppContext, RenderContext, Task,
+    actions, elements::*, AppContext, Entity, ModelHandle, MouseState, MutableAppContext,
-    View, ViewContext, ViewHandle,
+    RenderContext, Task, View, ViewContext, ViewHandle,
 };
 use picker::{Picker, PickerDelegate};
 use project::{Project, ProjectPath, WorktreeId};
@@ -226,7 +226,7 @@ impl PickerDelegate for FileFinder {
     fn render_match(
         &self,
         ix: usize,
-        mouse_state: &MouseState,
+        mouse_state: MouseState,
         selected: bool,
         cx: &AppContext,
     ) -> ElementBox {

crates/gpui/src/app.rs

@@ -7,7 +7,8 @@ use crate::{
     platform::{self, Platform, PromptLevel, WindowOptions},
     presenter::Presenter,
     util::post_inc,
-    AssetCache, AssetSource, ClipboardItem, FontCache, PathPromptOptions, TextLayoutCache,
+    AssetCache, AssetSource, ClipboardItem, FontCache, MouseRegionId, PathPromptOptions,
+    TextLayoutCache,
 };
 pub use action::*;
 use anyhow::{anyhow, Context, Result};
@@ -126,26 +127,6 @@ pub trait UpdateView {
         T: View;
 }
 
-pub trait ElementStateContext: DerefMut<Target = MutableAppContext> {
-    fn current_view_id(&self) -> usize;
-
-    fn element_state<Tag: 'static, T: 'static + Default>(
-        &mut self,
-        element_id: usize,
-    ) -> ElementStateHandle<T> {
-        let id = ElementStateId {
-            view_id: self.current_view_id(),
-            element_id,
-            tag: TypeId::of::<Tag>(),
-        };
-        self.cx
-            .element_states
-            .entry(id)
-            .or_insert_with(|| Box::new(T::default()));
-        ElementStateHandle::new(id, self.frame_count, &self.cx.ref_counts)
-    }
-}
-
 pub struct Menu<'a> {
     pub name: &'a str,
     pub items: Vec<MenuItem<'a>>,
@@ -467,6 +448,27 @@ impl TestAppContext {
         result
     }
 
+    pub fn render<F, V, T>(&mut self, handle: &ViewHandle<V>, f: F) -> T
+    where
+        F: FnOnce(&mut V, &mut RenderContext<V>) -> T,
+        V: View,
+    {
+        handle.update(&mut *self.cx.borrow_mut(), |view, cx| {
+            let mut render_cx = RenderContext {
+                app: cx,
+                window_id: handle.window_id(),
+                view_id: handle.id(),
+                view_type: PhantomData,
+                titlebar_height: 0.,
+                hovered_region_ids: Default::default(),
+                clicked_region_id: None,
+                right_clicked_region_id: None,
+                refreshing: false,
+            };
+            f(view, &mut render_cx)
+        })
+    }
+
     pub fn to_async(&self) -> AsyncAppContext {
         AsyncAppContext(self.cx.clone())
     }
@@ -1040,19 +1042,15 @@ impl MutableAppContext {
             .map_or(false, |window| window.is_active)
     }
 
-    pub fn render_view(
+    pub fn render_view(&mut self, params: RenderParams) -> Result<ElementBox> {
-        &mut self,
+        let window_id = params.window_id;
-        window_id: usize,
+        let view_id = params.view_id;
-        view_id: usize,
-        titlebar_height: f32,
-        refreshing: bool,
-    ) -> Result<ElementBox> {
         let mut view = self
             .cx
             .views
-            .remove(&(window_id, view_id))
+            .remove(&(params.window_id, params.view_id))
             .ok_or(anyhow!("view not found"))?;
-        let element = view.render(window_id, view_id, titlebar_height, refreshing, self);
+        let element = view.render(params, self);
         self.cx.views.insert((window_id, view_id), view);
         Ok(element)
     }
@@ -1079,7 +1077,15 @@ impl MutableAppContext {
             .map(|view_id| {
                 (
                     view_id,
-                    self.render_view(window_id, view_id, titlebar_height, false)
+                    self.render_view(RenderParams {
+                        window_id,
+                        view_id,
+                        titlebar_height,
+                        hovered_region_ids: Default::default(),
+                        clicked_region_id: None,
+                        right_clicked_region_id: None,
+                        refreshing: false,
+                    })
                     .unwrap(),
                 )
             })
@@ -1366,7 +1372,10 @@ impl MutableAppContext {
             .unwrap()
             .0
             .clone();
-        let dispatch_path = presenter.borrow().dispatch_path_from(view_id);
+        let mut dispatch_path = Vec::new();
+        presenter
+            .borrow()
+            .compute_dispatch_path_from(view_id, &mut dispatch_path);
         for view_id in dispatch_path {
             if let Some(view) = self.views.get(&(window_id, view_id)) {
                 let view_type = view.as_any().type_id();
@@ -1443,7 +1452,10 @@ impl MutableAppContext {
             .unwrap()
             .0
             .clone();
-        let dispatch_path = presenter.borrow().dispatch_path_from(view_id);
+        let mut dispatch_path = Vec::new();
+        presenter
+            .borrow()
+            .compute_dispatch_path_from(view_id, &mut dispatch_path);
         self.dispatch_action_any(window_id, &dispatch_path, action);
     }
 
@@ -1775,23 +1787,6 @@ impl MutableAppContext {
         )
     }
 
-    pub fn build_render_context<V: View>(
-        &mut self,
-        window_id: usize,
-        view_id: usize,
-        titlebar_height: f32,
-        refreshing: bool,
-    ) -> RenderContext<V> {
-        RenderContext {
-            app: self,
-            titlebar_height,
-            refreshing,
-            window_id,
-            view_id,
-            view_type: PhantomData,
-        }
-    }
-
     pub fn add_view<T, F>(&mut self, window_id: usize, build_view: F) -> ViewHandle<T>
     where
         T: View,
@@ -2917,14 +2912,7 @@ pub trait AnyView {
         cx: &mut MutableAppContext,
     ) -> Option<Pin<Box<dyn 'static + Future<Output = ()>>>>;
     fn ui_name(&self) -> &'static str;
-    fn render<'a>(
+    fn render<'a>(&mut self, params: RenderParams, cx: &mut MutableAppContext) -> ElementBox;
-        &mut self,
-        window_id: usize,
-        view_id: usize,
-        titlebar_height: f32,
-        refreshing: bool,
-        cx: &mut MutableAppContext,
-    ) -> ElementBox;
     fn on_focus(&mut self, cx: &mut MutableAppContext, window_id: usize, view_id: usize);
     fn on_blur(&mut self, cx: &mut MutableAppContext, window_id: usize, view_id: usize);
     fn keymap_context(&self, cx: &AppContext) -> keymap::Context;
@@ -2958,25 +2946,8 @@ where
         T::ui_name()
     }
 
-    fn render<'a>(
+    fn render<'a>(&mut self, params: RenderParams, cx: &mut MutableAppContext) -> ElementBox {
-        &mut self,
+        View::render(self, &mut RenderContext::new(params, cx))
-        window_id: usize,
-        view_id: usize,
-        titlebar_height: f32,
-        refreshing: bool,
-        cx: &mut MutableAppContext,
-    ) -> ElementBox {
-        View::render(
-            self,
-            &mut RenderContext {
-                window_id,
-                view_id,
-                app: cx,
-                view_type: PhantomData::<T>,
-                titlebar_height,
-                refreshing,
-            },
-        )
     }
 
     fn on_focus(&mut self, cx: &mut MutableAppContext, window_id: usize, view_id: usize) {
@@ -3458,23 +3429,86 @@ impl<'a, T: View> ViewContext<'a, T> {
     }
 }
 
+pub struct RenderParams {
+    pub window_id: usize,
+    pub view_id: usize,
+    pub titlebar_height: f32,
+    pub hovered_region_ids: HashSet<MouseRegionId>,
+    pub clicked_region_id: Option<MouseRegionId>,
+    pub right_clicked_region_id: Option<MouseRegionId>,
+    pub refreshing: bool,
+}
+
 pub struct RenderContext<'a, T: View> {
+    pub(crate) window_id: usize,
+    pub(crate) view_id: usize,
+    pub(crate) view_type: PhantomData<T>,
+    pub(crate) hovered_region_ids: HashSet<MouseRegionId>,
+    pub(crate) clicked_region_id: Option<MouseRegionId>,
+    pub(crate) right_clicked_region_id: Option<MouseRegionId>,
     pub app: &'a mut MutableAppContext,
     pub titlebar_height: f32,
     pub refreshing: bool,
-    window_id: usize,
-    view_id: usize,
-    view_type: PhantomData<T>,
 }
 
-impl<'a, T: View> RenderContext<'a, T> {
+#[derive(Clone, Copy, Default)]
-    pub fn handle(&self) -> WeakViewHandle<T> {
+pub struct MouseState {
+    pub hovered: bool,
+    pub clicked: bool,
+    pub right_clicked: bool,
+}
+
+impl<'a, V: View> RenderContext<'a, V> {
+    fn new(params: RenderParams, app: &'a mut MutableAppContext) -> Self {
+        Self {
+            app,
+            window_id: params.window_id,
+            view_id: params.view_id,
+            view_type: PhantomData,
+            titlebar_height: params.titlebar_height,
+            hovered_region_ids: params.hovered_region_ids.clone(),
+            clicked_region_id: params.clicked_region_id,
+            right_clicked_region_id: params.right_clicked_region_id,
+            refreshing: params.refreshing,
+        }
+    }
+
+    pub fn handle(&self) -> WeakViewHandle<V> {
         WeakViewHandle::new(self.window_id, self.view_id)
     }
 
     pub fn view_id(&self) -> usize {
         self.view_id
     }
+
+    pub fn mouse_state<Tag: 'static>(&self, region_id: usize) -> MouseState {
+        let region_id = MouseRegionId {
+            view_id: self.view_id,
+            tag: TypeId::of::<Tag>(),
+            region_id,
+        };
+        MouseState {
+            hovered: self.hovered_region_ids.contains(&region_id),
+            clicked: self.clicked_region_id == Some(region_id),
+            right_clicked: self.right_clicked_region_id == Some(region_id),
+        }
+    }
+
+    pub fn element_state<Tag: 'static, T: 'static + Default>(
+        &mut self,
+        element_id: usize,
+    ) -> ElementStateHandle<T> {
+        let id = ElementStateId {
+            view_id: self.view_id(),
+            element_id,
+            tag: TypeId::of::<Tag>(),
+        };
+        self.cx
+            .element_states
+            .entry(id)
+            .or_insert_with(|| Box::new(T::default()));
+        ElementStateHandle::new(id, self.frame_count, &self.cx.ref_counts)
+    }
 }
 
 impl AsRef<AppContext> for &AppContext {
@@ -3519,12 +3553,6 @@ impl<V: View> ReadView for RenderContext<'_, V> {
     }
 }
 
-impl<V: View> ElementStateContext for RenderContext<'_, V> {
-    fn current_view_id(&self) -> usize {
-        self.view_id
-    }
-}
-
 impl<M> AsRef<AppContext> for ViewContext<'_, M> {
     fn as_ref(&self) -> &AppContext {
         &self.app.cx
@@ -3584,6 +3612,16 @@ impl<V> UpgradeViewHandle for ViewContext<'_, V> {
     }
 }
 
+impl<V: View> UpgradeViewHandle for RenderContext<'_, V> {
+    fn upgrade_view_handle<T: View>(&self, handle: &WeakViewHandle<T>) -> Option<ViewHandle<T>> {
+        self.cx.upgrade_view_handle(handle)
+    }
+
+    fn upgrade_any_view_handle(&self, handle: &AnyWeakViewHandle) -> Option<AnyViewHandle> {
+        self.cx.upgrade_any_view_handle(handle)
+    }
+}
+
 impl<V: View> UpdateModel for ViewContext<'_, V> {
     fn update_model<T: Entity, O>(
         &mut self,
@@ -3613,12 +3651,6 @@ impl<V: View> UpdateView for ViewContext<'_, V> {
     }
 }
 
-impl<V: View> ElementStateContext for ViewContext<'_, V> {
-    fn current_view_id(&self) -> usize {
-        self.view_id
-    }
-}
-
 pub trait Handle<T> {
     type Weak: 'static;
     fn id(&self) -> usize;

crates/gpui/src/elements/container.rs

@@ -7,7 +7,7 @@ use crate::{
     },
     json::ToJson,
     platform::CursorStyle,
-    scene::{self, Border, Quad},
+    scene::{self, Border, CursorRegion, Quad},
     Element, ElementBox, Event, EventContext, LayoutContext, PaintContext, SizeConstraint,
 };
 use serde::Deserialize;
@@ -213,7 +213,10 @@ impl Element for Container {
         }
 
         if let Some(style) = self.style.cursor {
-            cx.scene.push_cursor_style(quad_bounds, style);
+            cx.scene.push_cursor_region(CursorRegion {
+                bounds: quad_bounds,
+                style,
+            });
         }
 
         let child_origin =

crates/gpui/src/elements/flex.rs

@@ -2,8 +2,8 @@ use std::{any::Any, f32::INFINITY};
 
 use crate::{
     json::{self, ToJson, Value},
-    Axis, DebugContext, Element, ElementBox, ElementStateContext, ElementStateHandle, Event,
+    Axis, DebugContext, Element, ElementBox, ElementStateHandle, Event, EventContext,
-    EventContext, LayoutContext, PaintContext, SizeConstraint, Vector2FExt,
+    LayoutContext, PaintContext, RenderContext, SizeConstraint, Vector2FExt, View,
 };
 use pathfinder_geometry::{
     rect::RectF,
@@ -40,15 +40,15 @@ impl Flex {
         Self::new(Axis::Vertical)
     }
 
-    pub fn scrollable<Tag, C>(
+    pub fn scrollable<Tag, V>(
         mut self,
         element_id: usize,
         scroll_to: Option<usize>,
-        cx: &mut C,
+        cx: &mut RenderContext<V>,
     ) -> Self
     where
         Tag: 'static,
-        C: ElementStateContext,
+        V: View,
     {
         let scroll_state = cx.element_state::<Tag, ScrollState>(element_id);
         scroll_state.update(cx, |scroll_state, _| scroll_state.scroll_to = scroll_to);

crates/gpui/src/elements/list.rs

@@ -5,7 +5,7 @@ use crate::{
     },
     json::json,
     DebugContext, Element, ElementBox, ElementRc, Event, EventContext, LayoutContext, PaintContext,
-    SizeConstraint,
+    RenderContext, SizeConstraint, View, ViewContext,
 };
 use std::{cell::RefCell, collections::VecDeque, ops::Range, rc::Rc};
 use sum_tree::{Bias, SumTree};
@@ -26,7 +26,7 @@ pub enum Orientation {
 
 struct StateInner {
     last_layout_width: Option<f32>,
-    render_item: Box<dyn FnMut(usize, &mut LayoutContext) -> ElementBox>,
+    render_item: Box<dyn FnMut(usize, &mut LayoutContext) -> Option<ElementBox>>,
     rendered_range: Range<usize>,
     items: SumTree<ListItem>,
     logical_scroll_top: Option<ListOffset>,
@@ -135,10 +135,13 @@ impl Element for List {
                 break;
             }
 
-            let element = state.render_item(scroll_top.item_ix + ix, item, item_constraint, cx);
+            if let Some(element) =
+                state.render_item(scroll_top.item_ix + ix, item, item_constraint, cx)
+            {
                 rendered_height += element.size().y();
                 rendered_items.push_back(ListItem::Rendered(element));
             }
+        }
 
         // Prepare to start walking upward from the item at the scroll top.
         cursor.seek(&Count(scroll_top.item_ix), Bias::Right, &());
@@ -149,9 +152,12 @@ impl Element for List {
             while rendered_height < size.y() {
                 cursor.prev(&());
                 if let Some(item) = cursor.item() {
-                    let element = state.render_item(cursor.start().0, item, item_constraint, cx);
+                    if let Some(element) =
+                        state.render_item(cursor.start().0, item, item_constraint, cx)
+                    {
                         rendered_height += element.size().y();
                         rendered_items.push_front(ListItem::Rendered(element));
+                    }
                 } else {
                     break;
                 }
@@ -182,9 +188,12 @@ impl Element for List {
         while leading_overdraw < state.overdraw {
             cursor.prev(&());
             if let Some(item) = cursor.item() {
-                let element = state.render_item(cursor.start().0, item, item_constraint, cx);
+                if let Some(element) =
+                    state.render_item(cursor.start().0, item, item_constraint, cx)
+                {
                     leading_overdraw += element.size().y();
                     rendered_items.push_front(ListItem::Rendered(element));
+                }
             } else {
                 break;
             }
@@ -330,20 +339,25 @@ impl Element for List {
 }
 
 impl ListState {
-    pub fn new<F>(
+    pub fn new<F, V>(
         element_count: usize,
         orientation: Orientation,
         overdraw: f32,
-        render_item: F,
+        cx: &mut ViewContext<V>,
+        mut render_item: F,
     ) -> Self
     where
-        F: 'static + FnMut(usize, &mut LayoutContext) -> ElementBox,
+        V: View,
+        F: 'static + FnMut(&mut V, usize, &mut RenderContext<V>) -> ElementBox,
     {
         let mut items = SumTree::new();
         items.extend((0..element_count).map(|_| ListItem::Unrendered), &());
+        let handle = cx.handle();
         Self(Rc::new(RefCell::new(StateInner {
             last_layout_width: None,
-            render_item: Box::new(render_item),
+            render_item: Box::new(move |ix, cx| {
+                Some(cx.render(&handle, |view, cx| render_item(view, ix, cx)))
+            }),
             rendered_range: 0..0,
             items,
             logical_scroll_top: None,
@@ -414,13 +428,13 @@ impl StateInner {
         existing_item: &ListItem,
         constraint: SizeConstraint,
         cx: &mut LayoutContext,
-    ) -> ElementRc {
+    ) -> Option<ElementRc> {
         if let ListItem::Rendered(element) = existing_item {
-            element.clone()
+            Some(element.clone())
         } else {
-            let mut element = (self.render_item)(ix, cx);
+            let mut element = (self.render_item)(ix, cx)?;
             element.layout(constraint, cx);
-            element.into()
+            Some(element.into())
         }
     }
 
@@ -593,22 +607,26 @@ impl<'a> sum_tree::SeekTarget<'a, ListItemSummary, ListItemSummary> for Height {
 #[cfg(test)]
 mod tests {
     use super::*;
-    use crate::geometry::vector::vec2f;
+    use crate::{elements::Empty, geometry::vector::vec2f, Entity};
     use rand::prelude::*;
     use std::env;
 
     #[crate::test(self)]
     fn test_layout(cx: &mut crate::MutableAppContext) {
         let mut presenter = cx.build_presenter(0, 0.);
+        let (_, view) = cx.add_window(Default::default(), |_| TestView);
         let constraint = SizeConstraint::new(vec2f(0., 0.), vec2f(100., 40.));
 
         let elements = Rc::new(RefCell::new(vec![(0, 20.), (1, 30.), (2, 100.)]));
-        let state = ListState::new(elements.borrow().len(), Orientation::Top, 1000.0, {
+
+        let state = view.update(cx, |_, cx| {
+            ListState::new(elements.borrow().len(), Orientation::Top, 1000.0, cx, {
                 let elements = elements.clone();
-            move |ix, _| {
+                move |_, ix, _| {
                     let (id, height) = elements.borrow()[ix];
                     TestElement::new(id, height).boxed()
                 }
+            })
         });
 
         let mut list = List::new(state.clone());
@@ -694,6 +712,7 @@ mod tests {
             .map(|i| i.parse().expect("invalid `OPERATIONS` variable"))
             .unwrap_or(10);
 
+        let (_, view) = cx.add_window(Default::default(), |_| TestView);
         let mut presenter = cx.build_presenter(0, 0.);
         let mut next_id = 0;
         let elements = Rc::new(RefCell::new(
@@ -709,12 +728,15 @@ mod tests {
             .choose(&mut rng)
             .unwrap();
         let overdraw = rng.gen_range(1..=100) as f32;
-        let state = ListState::new(elements.borrow().len(), orientation, overdraw, {
+
+        let state = view.update(cx, |_, cx| {
+            ListState::new(elements.borrow().len(), orientation, overdraw, cx, {
                 let elements = elements.clone();
-            move |ix, _| {
+                move |_, ix, _| {
                     let (id, height) = elements.borrow()[ix];
                     TestElement::new(id, height).boxed()
                 }
+            })
         });
 
         let mut width = rng.gen_range(0..=2000) as f32 / 2.;
@@ -851,6 +873,22 @@ mod tests {
         }
     }
 
+    struct TestView;
+
+    impl Entity for TestView {
+        type Event = ();
+    }
+
+    impl View for TestView {
+        fn ui_name() -> &'static str {
+            "TestView"
+        }
+
+        fn render(&mut self, _: &mut RenderContext<'_, Self>) -> ElementBox {
+            Empty::new().boxed()
+        }
+    }
+
     struct TestElement {
         id: usize,
         size: Vector2F,

crates/gpui/src/elements/mouse_event_handler.rs

@@ -1,3 +1,5 @@
+use std::{any::TypeId, rc::Rc};
+
 use super::Padding;
 use crate::{
     geometry::{
@@ -5,49 +7,42 @@ use crate::{
         vector::{vec2f, Vector2F},
     },
     platform::CursorStyle,
-    DebugContext, Element, ElementBox, ElementStateContext, ElementStateHandle, Event,
+    scene::CursorRegion,
-    EventContext, LayoutContext, PaintContext, SizeConstraint,
+    DebugContext, Element, ElementBox, Event, EventContext, LayoutContext, MouseRegion, MouseState,
+    PaintContext, RenderContext, SizeConstraint, View,
 };
 use serde_json::json;
 
 pub struct MouseEventHandler {
-    state: ElementStateHandle<MouseState>,
     child: ElementBox,
+    tag: TypeId,
+    id: usize,
     cursor_style: Option<CursorStyle>,
-    mouse_down_handler: Option<Box<dyn FnMut(Vector2F, &mut EventContext)>>,
+    mouse_down_handler: Option<Rc<dyn Fn(Vector2F, &mut EventContext)>>,
-    click_handler: Option<Box<dyn FnMut(Vector2F, usize, &mut EventContext)>>,
+    click_handler: Option<Rc<dyn Fn(Vector2F, usize, &mut EventContext)>>,
-    drag_handler: Option<Box<dyn FnMut(Vector2F, &mut EventContext)>>,
+    right_mouse_down_handler: Option<Rc<dyn Fn(Vector2F, &mut EventContext)>>,
-    right_mouse_down_handler: Option<Box<dyn FnMut(Vector2F, &mut EventContext)>>,
+    right_click_handler: Option<Rc<dyn Fn(Vector2F, usize, &mut EventContext)>>,
-    right_click_handler: Option<Box<dyn FnMut(Vector2F, usize, &mut EventContext)>>,
+    drag_handler: Option<Rc<dyn Fn(Vector2F, &mut EventContext)>>,
     padding: Padding,
 }
 
-#[derive(Default, Debug)]
-pub struct MouseState {
-    pub hovered: bool,
-    pub clicked: bool,
-    pub right_clicked: bool,
-    prev_drag_position: Option<Vector2F>,
-}
-
 impl MouseEventHandler {
-    pub fn new<Tag, C, F>(id: usize, cx: &mut C, render_child: F) -> Self
+    pub fn new<Tag, V, F>(id: usize, cx: &mut RenderContext<V>, render_child: F) -> Self
     where
         Tag: 'static,
-        C: ElementStateContext,
+        V: View,
-        F: FnOnce(&MouseState, &mut C) -> ElementBox,
+        F: FnOnce(MouseState, &mut RenderContext<V>) -> ElementBox,
     {
-        let state_handle = cx.element_state::<Tag, _>(id);
-        let child = state_handle.update(cx, |state, cx| render_child(state, cx));
         Self {
-            state: state_handle,
+            id,
-            child,
+            tag: TypeId::of::<Tag>(),
+            child: render_child(cx.mouse_state::<Tag>(id), cx),
             cursor_style: None,
             mouse_down_handler: None,
             click_handler: None,
-            drag_handler: None,
             right_mouse_down_handler: None,
             right_click_handler: None,
+            drag_handler: None,
             padding: Default::default(),
         }
     }
@@ -59,38 +54,38 @@ impl MouseEventHandler {
 
     pub fn on_mouse_down(
         mut self,
-        handler: impl FnMut(Vector2F, &mut EventContext) + 'static,
+        handler: impl Fn(Vector2F, &mut EventContext) + 'static,
     ) -> Self {
-        self.mouse_down_handler = Some(Box::new(handler));
+        self.mouse_down_handler = Some(Rc::new(handler));
         self
     }
 
     pub fn on_click(
         mut self,
-        handler: impl FnMut(Vector2F, usize, &mut EventContext) + 'static,
+        handler: impl Fn(Vector2F, usize, &mut EventContext) + 'static,
     ) -> Self {
-        self.click_handler = Some(Box::new(handler));
+        self.click_handler = Some(Rc::new(handler));
-        self
-    }
-
-    pub fn on_drag(mut self, handler: impl FnMut(Vector2F, &mut EventContext) + 'static) -> Self {
-        self.drag_handler = Some(Box::new(handler));
         self
     }
 
     pub fn on_right_mouse_down(
         mut self,
-        handler: impl FnMut(Vector2F, &mut EventContext) + 'static,
+        handler: impl Fn(Vector2F, &mut EventContext) + 'static,
     ) -> Self {
-        self.right_mouse_down_handler = Some(Box::new(handler));
+        self.right_mouse_down_handler = Some(Rc::new(handler));
         self
     }
 
     pub fn on_right_click(
         mut self,
-        handler: impl FnMut(Vector2F, usize, &mut EventContext) + 'static,
+        handler: impl Fn(Vector2F, usize, &mut EventContext) + 'static,
     ) -> Self {
-        self.right_click_handler = Some(Box::new(handler));
+        self.right_click_handler = Some(Rc::new(handler));
+        self
+    }
+
+    pub fn on_drag(mut self, handler: impl Fn(Vector2F, &mut EventContext) + 'static) -> Self {
+        self.drag_handler = Some(Rc::new(handler));
         self
     }
 
@@ -127,10 +122,26 @@ impl Element for MouseEventHandler {
         _: &mut Self::LayoutState,
         cx: &mut PaintContext,
     ) -> Self::PaintState {
-        if let Some(cursor_style) = self.cursor_style {
+        if let Some(style) = self.cursor_style {
-            cx.scene
+            cx.scene.push_cursor_region(CursorRegion {
-                .push_cursor_style(self.hit_bounds(bounds), cursor_style);
+                bounds: self.hit_bounds(bounds),
+                style,
+            });
         }
+
+        cx.scene.push_mouse_region(MouseRegion {
+            view_id: cx.current_view_id(),
+            tag: self.tag,
+            region_id: self.id,
+            bounds: self.hit_bounds(bounds),
+            hover: None,
+            click: self.click_handler.clone(),
+            mouse_down: self.mouse_down_handler.clone(),
+            right_click: self.right_click_handler.clone(),
+            right_mouse_down: self.right_mouse_down_handler.clone(),
+            drag: self.drag_handler.clone(),
+        });
+
         self.child.paint(bounds.origin(), visible_bounds, cx);
     }
 
@@ -138,113 +149,12 @@ impl Element for MouseEventHandler {
         &mut self,
         event: &Event,
         _: RectF,
-        visible_bounds: RectF,
+        _: RectF,
         _: &mut Self::LayoutState,
         _: &mut Self::PaintState,
         cx: &mut EventContext,
     ) -> bool {
-        let hit_bounds = self.hit_bounds(visible_bounds);
+        self.child.dispatch_event(event, cx)
-        let mouse_down_handler = self.mouse_down_handler.as_mut();
-        let click_handler = self.click_handler.as_mut();
-        let drag_handler = self.drag_handler.as_mut();
-        let right_mouse_down_handler = self.right_mouse_down_handler.as_mut();
-        let right_click_handler = self.right_click_handler.as_mut();
-
-        let handled_in_child = self.child.dispatch_event(event, cx);
-
-        self.state.update(cx, |state, cx| match event {
-            Event::MouseMoved {
-                position,
-                left_mouse_down,
-            } => {
-                if !left_mouse_down {
-                    let mouse_in = hit_bounds.contains_point(*position);
-                    if state.hovered != mouse_in {
-                        state.hovered = mouse_in;
-                        cx.notify();
-                        return true;
-                    }
-                }
-                handled_in_child
-            }
-            Event::LeftMouseDown { position, .. } => {
-                if !handled_in_child && hit_bounds.contains_point(*position) {
-                    state.clicked = true;
-                    state.prev_drag_position = Some(*position);
-                    cx.notify();
-                    if let Some(handler) = mouse_down_handler {
-                        handler(*position, cx);
-                    }
-                    true
-                } else {
-                    handled_in_child
-                }
-            }
-            Event::LeftMouseUp {
-                position,
-                click_count,
-                ..
-            } => {
-                state.prev_drag_position = None;
-                if !handled_in_child && state.clicked {
-                    state.clicked = false;
-                    cx.notify();
-                    if let Some(handler) = click_handler {
-                        if hit_bounds.contains_point(*position) {
-                            handler(*position, *click_count, cx);
-                        }
-                    }
-                    true
-                } else {
-                    handled_in_child
-                }
-            }
-            Event::LeftMouseDragged { position, .. } => {
-                if !handled_in_child && state.clicked {
-                    let prev_drag_position = state.prev_drag_position.replace(*position);
-                    if let Some((handler, prev_position)) = drag_handler.zip(prev_drag_position) {
-                        let delta = *position - prev_position;
-                        if !delta.is_zero() {
-                            (handler)(delta, cx);
-                        }
-                    }
-                    true
-                } else {
-                    handled_in_child
-                }
-            }
-            Event::RightMouseDown { position, .. } => {
-                if !handled_in_child && hit_bounds.contains_point(*position) {
-                    state.right_clicked = true;
-                    cx.notify();
-                    if let Some(handler) = right_mouse_down_handler {
-                        handler(*position, cx);
-                    }
-                    true
-                } else {
-                    handled_in_child
-                }
-            }
-            Event::RightMouseUp {
-                position,
-                click_count,
-                ..
-            } => {
-                if !handled_in_child && state.right_clicked {
-                    state.right_clicked = false;
-                    cx.notify();
-                    if let Some(handler) = right_click_handler {
-                        if hit_bounds.contains_point(*position) {
-                            handler(*position, *click_count, cx);
-                        }
-                    }
-                    true
-                } else {
-                    handled_in_child
-                }
-            }
-            _ => handled_in_child,
-        })
     }
 
     fn debug(

crates/gpui/src/elements/uniform_list.rs

@@ -5,7 +5,7 @@ use crate::{
         vector::{vec2f, Vector2F},
     },
     json::{self, json},
-    ElementBox,
+    ElementBox, RenderContext, View,
 };
 use json::ToJson;
 use std::{cell::RefCell, cmp, ops::Range, rc::Rc};
@@ -41,27 +41,37 @@ pub struct LayoutState {
     items: Vec<ElementBox>,
 }
 
-pub struct UniformList<F>
+pub struct UniformList {
-where
-    F: Fn(Range<usize>, &mut Vec<ElementBox>, &mut LayoutContext),
-{
     state: UniformListState,
     item_count: usize,
-    append_items: F,
+    append_items: Box<dyn Fn(Range<usize>, &mut Vec<ElementBox>, &mut LayoutContext)>,
     padding_top: f32,
     padding_bottom: f32,
     get_width_from_item: Option<usize>,
 }
 
-impl<F> UniformList<F>
+impl UniformList {
+    pub fn new<F, V>(
+        state: UniformListState,
+        item_count: usize,
+        cx: &mut RenderContext<V>,
+        append_items: F,
+    ) -> Self
     where
-    F: Fn(Range<usize>, &mut Vec<ElementBox>, &mut LayoutContext),
+        V: View,
+        F: 'static + Fn(&mut V, Range<usize>, &mut Vec<ElementBox>, &mut RenderContext<V>),
     {
-    pub fn new(state: UniformListState, item_count: usize, append_items: F) -> Self {
+        let handle = cx.handle();
         Self {
             state,
             item_count,
-            append_items,
+            append_items: Box::new(move |range, items, cx| {
+                if let Some(handle) = handle.upgrade(cx) {
+                    cx.render(&handle, |view, cx| {
+                        append_items(view, range, items, cx);
+                    });
+                }
+            }),
             padding_top: 0.,
             padding_bottom: 0.,
             get_width_from_item: None,
@@ -144,10 +154,7 @@ where
     }
 }
 
-impl<F> Element for UniformList<F>
+impl Element for UniformList {
-where
-    F: Fn(Range<usize>, &mut Vec<ElementBox>, &mut LayoutContext),
-{
     type LayoutState = LayoutState;
     type PaintState = ();
 
@@ -162,8 +169,7 @@ where
             );
         }
 
-        if self.item_count == 0 {
+        let no_items = (
-            return (
             constraint.min,
             LayoutState {
                 item_height: 0.,
@@ -171,24 +177,32 @@ where
                 items: Default::default(),
             },
         );
+
+        if self.item_count == 0 {
+            return no_items;
         }
 
         let mut items = Vec::new();
         let mut size = constraint.max;
         let mut item_size;
         let sample_item_ix;
-        let mut sample_item;
+        let sample_item;
         if let Some(sample_ix) = self.get_width_from_item {
             (self.append_items)(sample_ix..sample_ix + 1, &mut items, cx);
             sample_item_ix = sample_ix;
-            sample_item = items.pop().unwrap();
+
-            item_size = sample_item.layout(constraint, cx);
+            if let Some(mut item) = items.pop() {
+                item_size = item.layout(constraint, cx);
                 size.set_x(item_size.x());
+                sample_item = item;
+            } else {
+                return no_items;
+            }
         } else {
             (self.append_items)(0..1, &mut items, cx);
             sample_item_ix = 0;
-            sample_item = items.pop().unwrap();
+            if let Some(mut item) = items.pop() {
-            item_size = sample_item.layout(
+                item_size = item.layout(
                     SizeConstraint::new(
                         vec2f(constraint.max.x(), 0.0),
                         vec2f(constraint.max.x(), f32::INFINITY),
@@ -196,6 +210,10 @@ where
                     cx,
                 );
                 item_size.set_x(size.x());
+                sample_item = item
+            } else {
+                return no_items;
+            }
         }
 
         let item_constraint = SizeConstraint {

crates/gpui/src/gpui.rs

@@ -16,7 +16,7 @@ pub mod fonts;
 pub mod geometry;
 mod presenter;
 mod scene;
-pub use scene::{Border, Quad, Scene};
+pub use scene::{Border, CursorRegion, MouseRegion, MouseRegionId, Quad, Scene};
 pub mod text_layout;
 pub use text_layout::TextLayoutCache;
 mod util;

crates/gpui/src/presenter.rs

@@ -6,16 +6,19 @@ use crate::{
     json::{self, ToJson},
     keymap::Keystroke,
     platform::{CursorStyle, Event},
+    scene::CursorRegion,
     text_layout::TextLayoutCache,
-    Action, AnyModelHandle, AnyViewHandle, AnyWeakModelHandle, AssetCache, ElementBox,
+    Action, AnyModelHandle, AnyViewHandle, AnyWeakModelHandle, AssetCache, ElementBox, Entity,
-    ElementStateContext, Entity, FontSystem, ModelHandle, ReadModel, ReadView, Scene,
+    FontSystem, ModelHandle, MouseRegion, MouseRegionId, ReadModel, ReadView, RenderContext,
-    UpgradeModelHandle, UpgradeViewHandle, View, ViewHandle, WeakModelHandle, WeakViewHandle,
+    RenderParams, Scene, UpgradeModelHandle, UpgradeViewHandle, View, ViewHandle, WeakModelHandle,
+    WeakViewHandle,
 };
 use pathfinder_geometry::vector::{vec2f, Vector2F};
 use serde_json::json;
 use smallvec::SmallVec;
 use std::{
     collections::{HashMap, HashSet},
+    marker::PhantomData,
     ops::{Deref, DerefMut},
     sync::Arc,
 };
@@ -24,11 +27,16 @@ pub struct Presenter {
     window_id: usize,
     pub(crate) rendered_views: HashMap<usize, ElementBox>,
     parents: HashMap<usize, usize>,
-    cursor_styles: Vec<(RectF, CursorStyle)>,
+    cursor_regions: Vec<CursorRegion>,
+    mouse_regions: Vec<MouseRegion>,
     font_cache: Arc<FontCache>,
     text_layout_cache: TextLayoutCache,
     asset_cache: Arc<AssetCache>,
     last_mouse_moved_event: Option<Event>,
+    hovered_region_ids: HashSet<MouseRegionId>,
+    clicked_region: Option<MouseRegion>,
+    right_clicked_region: Option<MouseRegion>,
+    prev_drag_position: Option<Vector2F>,
     titlebar_height: f32,
 }
 
@@ -45,32 +53,35 @@ impl Presenter {
             window_id,
             rendered_views: cx.render_views(window_id, titlebar_height),
             parents: HashMap::new(),
-            cursor_styles: Default::default(),
+            cursor_regions: Default::default(),
+            mouse_regions: Default::default(),
             font_cache,
             text_layout_cache,
             asset_cache,
             last_mouse_moved_event: None,
+            hovered_region_ids: Default::default(),
+            clicked_region: None,
+            right_clicked_region: None,
+            prev_drag_position: None,
             titlebar_height,
         }
     }
 
     pub fn dispatch_path(&self, app: &AppContext) -> Vec<usize> {
+        let mut path = Vec::new();
         if let Some(view_id) = app.focused_view_id(self.window_id) {
-            self.dispatch_path_from(view_id)
+            self.compute_dispatch_path_from(view_id, &mut path)
-        } else {
-            Vec::new()
         }
+        path
     }
 
-    pub(crate) fn dispatch_path_from(&self, mut view_id: usize) -> Vec<usize> {
+    pub(crate) fn compute_dispatch_path_from(&self, mut view_id: usize, path: &mut Vec<usize>) {
-        let mut path = Vec::new();
         path.push(view_id);
         while let Some(parent_id) = self.parents.get(&view_id).copied() {
             path.push(parent_id);
             view_id = parent_id;
         }
         path.reverse();
-        path
     }
 
     pub fn invalidate(
@@ -87,7 +98,18 @@ impl Presenter {
         for view_id in &invalidation.updated {
             self.rendered_views.insert(
                 *view_id,
-                cx.render_view(self.window_id, *view_id, self.titlebar_height, false)
+                cx.render_view(RenderParams {
+                    window_id: self.window_id,
+                    view_id: *view_id,
+                    titlebar_height: self.titlebar_height,
+                    hovered_region_ids: self.hovered_region_ids.clone(),
+                    clicked_region_id: self.clicked_region.as_ref().map(MouseRegion::id),
+                    right_clicked_region_id: self
+                        .right_clicked_region
+                        .as_ref()
+                        .map(MouseRegion::id),
+                    refreshing: false,
+                })
                 .unwrap(),
             );
         }
@@ -98,7 +120,18 @@ impl Presenter {
         for (view_id, view) in &mut self.rendered_views {
             if !invalidation.updated.contains(view_id) {
                 *view = cx
-                    .render_view(self.window_id, *view_id, self.titlebar_height, true)
+                    .render_view(RenderParams {
+                        window_id: self.window_id,
+                        view_id: *view_id,
+                        titlebar_height: self.titlebar_height,
+                        hovered_region_ids: self.hovered_region_ids.clone(),
+                        clicked_region_id: self.clicked_region.as_ref().map(MouseRegion::id),
+                        right_clicked_region_id: self
+                            .right_clicked_region
+                            .as_ref()
+                            .map(MouseRegion::id),
+                        refreshing: true,
+                    })
                     .unwrap();
             }
         }
@@ -122,7 +155,8 @@ impl Presenter {
                 RectF::new(Vector2F::zero(), window_size),
             );
             self.text_layout_cache.finish_frame();
-            self.cursor_styles = scene.cursor_styles();
+            self.cursor_regions = scene.cursor_regions();
+            self.mouse_regions = scene.mouse_regions();
 
             if cx.window_is_active(self.window_id) {
                 if let Some(event) = self.last_mouse_moved_event.clone() {
@@ -153,13 +187,17 @@ impl Presenter {
             window_id: self.window_id,
             rendered_views: &mut self.rendered_views,
             parents: &mut self.parents,
-            refreshing,
-            window_size,
             font_cache: &self.font_cache,
             font_system: cx.platform().fonts(),
             text_layout_cache: &self.text_layout_cache,
             asset_cache: &self.asset_cache,
             view_stack: Vec::new(),
+            refreshing,
+            hovered_region_ids: self.hovered_region_ids.clone(),
+            clicked_region_id: self.clicked_region.as_ref().map(MouseRegion::id),
+            right_clicked_region_id: self.right_clicked_region.as_ref().map(MouseRegion::id),
+            titlebar_height: self.titlebar_height,
+            window_size,
             app: cx,
         }
     }
@@ -174,13 +212,69 @@ impl Presenter {
             font_cache: &self.font_cache,
             text_layout_cache: &self.text_layout_cache,
             rendered_views: &mut self.rendered_views,
+            view_stack: Vec::new(),
             app: cx,
         }
     }
 
     pub fn dispatch_event(&mut self, event: Event, cx: &mut MutableAppContext) {
         if let Some(root_view_id) = cx.root_view_id(self.window_id) {
+            let mut invalidated_views = Vec::new();
+            let mut hovered_regions = Vec::new();
+            let mut unhovered_regions = Vec::new();
+            let mut mouse_down_region = None;
+            let mut clicked_region = None;
+            let mut right_mouse_down_region = None;
+            let mut right_clicked_region = None;
+            let mut dragged_region = None;
+
             match event {
+                Event::LeftMouseDown { position, .. } => {
+                    for region in self.mouse_regions.iter().rev() {
+                        if region.bounds.contains_point(position) {
+                            invalidated_views.push(region.view_id);
+                            mouse_down_region = Some((region.clone(), position));
+                            self.clicked_region = Some(region.clone());
+                            self.prev_drag_position = Some(position);
+                            break;
+                        }
+                    }
+                }
+                Event::LeftMouseUp {
+                    position,
+                    click_count,
+                    ..
+                } => {
+                    self.prev_drag_position.take();
+                    if let Some(region) = self.clicked_region.take() {
+                        invalidated_views.push(region.view_id);
+                        if region.bounds.contains_point(position) {
+                            clicked_region = Some((region, position, click_count));
+                        }
+                    }
+                }
+                Event::RightMouseDown { position, .. } => {
+                    for region in self.mouse_regions.iter().rev() {
+                        if region.bounds.contains_point(position) {
+                            invalidated_views.push(region.view_id);
+                            right_mouse_down_region = Some((region.clone(), position));
+                            self.right_clicked_region = Some(region.clone());
+                            break;
+                        }
+                    }
+                }
+                Event::RightMouseUp {
+                    position,
+                    click_count,
+                    ..
+                } => {
+                    if let Some(region) = self.right_clicked_region.take() {
+                        invalidated_views.push(region.view_id);
+                        if region.bounds.contains_point(position) {
+                            right_clicked_region = Some((region, position, click_count));
+                        }
+                    }
+                }
                 Event::MouseMoved {
                     position,
                     left_mouse_down,
@@ -189,16 +283,43 @@ impl Presenter {
 
                     if !left_mouse_down {
                         let mut style_to_assign = CursorStyle::Arrow;
-                        for (bounds, style) in self.cursor_styles.iter().rev() {
+                        for region in self.cursor_regions.iter().rev() {
-                            if bounds.contains_point(position) {
+                            if region.bounds.contains_point(position) {
-                                style_to_assign = *style;
+                                style_to_assign = region.style;
                                 break;
                             }
                         }
                         cx.platform().set_cursor_style(style_to_assign);
+
+                        for region in self.mouse_regions.iter().rev() {
+                            let region_id = region.id();
+                            if region.bounds.contains_point(position) {
+                                if !self.hovered_region_ids.contains(&region_id) {
+                                    invalidated_views.push(region.view_id);
+                                    hovered_regions.push(region.clone());
+                                    self.hovered_region_ids.insert(region_id);
+                                }
+                            } else {
+                                if self.hovered_region_ids.contains(&region_id) {
+                                    invalidated_views.push(region.view_id);
+                                    unhovered_regions.push(region.clone());
+                                    self.hovered_region_ids.remove(&region_id);
+                                }
+                            }
+                        }
                     }
                 }
                 Event::LeftMouseDragged { position } => {
+                    if let Some((clicked_region, prev_drag_position)) = self
+                        .clicked_region
+                        .as_ref()
+                        .zip(self.prev_drag_position.as_mut())
+                    {
+                        dragged_region =
+                            Some((clicked_region.clone(), position - *prev_drag_position));
+                        *prev_drag_position = position;
+                    }
+
                     self.last_mouse_moved_event = Some(Event::MouseMoved {
                         position,
                         left_mouse_down: true,
@@ -208,16 +329,88 @@ impl Presenter {
             }
 
             let mut event_cx = self.build_event_context(cx);
-            event_cx.dispatch_event(root_view_id, &event);
+            let mut handled = false;
+            for unhovered_region in unhovered_regions {
+                if let Some(hover_callback) = unhovered_region.hover {
+                    handled = true;
+                    event_cx.with_current_view(unhovered_region.view_id, |event_cx| {
+                        hover_callback(false, event_cx);
+                    })
+                }
+            }
 
-            let invalidated_views = event_cx.invalidated_views;
+            for hovered_region in hovered_regions {
+                if let Some(hover_callback) = hovered_region.hover {
+                    handled = true;
+                    event_cx.with_current_view(hovered_region.view_id, |event_cx| {
+                        hover_callback(true, event_cx);
+                    })
+                }
+            }
+
+            if let Some((mouse_down_region, position)) = mouse_down_region {
+                if let Some(mouse_down_callback) = mouse_down_region.mouse_down {
+                    handled = true;
+                    event_cx.with_current_view(mouse_down_region.view_id, |event_cx| {
+                        mouse_down_callback(position, event_cx);
+                    })
+                }
+            }
+
+            if let Some((clicked_region, position, click_count)) = clicked_region {
+                if let Some(click_callback) = clicked_region.click {
+                    handled = true;
+                    event_cx.with_current_view(clicked_region.view_id, |event_cx| {
+                        click_callback(position, click_count, event_cx);
+                    })
+                }
+            }
+
+            if let Some((right_mouse_down_region, position)) = right_mouse_down_region {
+                if let Some(right_mouse_down_callback) = right_mouse_down_region.right_mouse_down {
+                    handled = true;
+                    event_cx.with_current_view(right_mouse_down_region.view_id, |event_cx| {
+                        right_mouse_down_callback(position, event_cx);
+                    })
+                }
+            }
+
+            if let Some((right_clicked_region, position, click_count)) = right_clicked_region {
+                if let Some(right_click_callback) = right_clicked_region.right_click {
+                    handled = true;
+                    event_cx.with_current_view(right_clicked_region.view_id, |event_cx| {
+                        right_click_callback(position, click_count, event_cx);
+                    })
+                }
+            }
+
+            if let Some((dragged_region, delta)) = dragged_region {
+                if let Some(drag_callback) = dragged_region.drag {
+                    handled = true;
+                    event_cx.with_current_view(dragged_region.view_id, |event_cx| {
+                        drag_callback(delta, event_cx);
+                    })
+                }
+            }
+
+            if !handled {
+                event_cx.dispatch_event(root_view_id, &event);
+            }
+
+            invalidated_views.extend(event_cx.invalidated_views);
             let dispatch_directives = event_cx.dispatched_actions;
 
             for view_id in invalidated_views {
                 cx.notify_view(self.window_id, view_id);
             }
+
+            let mut dispatch_path = Vec::new();
             for directive in dispatch_directives {
-                cx.dispatch_action_any(self.window_id, &directive.path, directive.action.as_ref());
+                dispatch_path.clear();
+                if let Some(view_id) = directive.dispatcher_view_id {
+                    self.compute_dispatch_path_from(view_id, &mut dispatch_path);
+                }
+                cx.dispatch_action_any(self.window_id, &dispatch_path, directive.action.as_ref());
             }
         }
     }
@@ -255,7 +448,7 @@ impl Presenter {
 }
 
 pub struct DispatchDirective {
-    pub path: Vec<usize>,
+    pub dispatcher_view_id: Option<usize>,
     pub action: Box<dyn Action>,
 }
 
@@ -264,16 +457,28 @@ pub struct LayoutContext<'a> {
     rendered_views: &'a mut HashMap<usize, ElementBox>,
     parents: &'a mut HashMap<usize, usize>,
     view_stack: Vec<usize>,
-    pub refreshing: bool,
-    pub window_size: Vector2F,
     pub font_cache: &'a Arc<FontCache>,
     pub font_system: Arc<dyn FontSystem>,
     pub text_layout_cache: &'a TextLayoutCache,
     pub asset_cache: &'a AssetCache,
     pub app: &'a mut MutableAppContext,
+    pub refreshing: bool,
+    pub window_size: Vector2F,
+    titlebar_height: f32,
+    hovered_region_ids: HashSet<MouseRegionId>,
+    clicked_region_id: Option<MouseRegionId>,
+    right_clicked_region_id: Option<MouseRegionId>,
 }
 
 impl<'a> LayoutContext<'a> {
+    pub(crate) fn keystrokes_for_action(
+        &self,
+        action: &dyn Action,
+    ) -> Option<SmallVec<[Keystroke; 2]>> {
+        self.app
+            .keystrokes_for_action(self.window_id, &self.view_stack, action)
+    }
+
     fn layout(&mut self, view_id: usize, constraint: SizeConstraint) -> Vector2F {
         if let Some(parent_id) = self.view_stack.last() {
             self.parents.insert(view_id, *parent_id);
@@ -286,12 +491,25 @@ impl<'a> LayoutContext<'a> {
         size
     }
 
-    pub(crate) fn keystrokes_for_action(
+    pub fn render<F, V, T>(&mut self, handle: &ViewHandle<V>, f: F) -> T
-        &self,
+    where
-        action: &dyn Action,
+        F: FnOnce(&mut V, &mut RenderContext<V>) -> T,
-    ) -> Option<SmallVec<[Keystroke; 2]>> {
+        V: View,
-        self.app
+    {
-            .keystrokes_for_action(self.window_id, &self.view_stack, action)
+        handle.update(self.app, |view, cx| {
+            let mut render_cx = RenderContext {
+                app: cx,
+                window_id: handle.window_id(),
+                view_id: handle.id(),
+                view_type: PhantomData,
+                titlebar_height: self.titlebar_height,
+                hovered_region_ids: self.hovered_region_ids.clone(),
+                clicked_region_id: self.clicked_region_id,
+                right_clicked_region_id: self.right_clicked_region_id,
+                refreshing: self.refreshing,
+            };
+            f(view, &mut render_cx)
+        })
     }
 }
 
@@ -348,14 +566,9 @@ impl<'a> UpgradeViewHandle for LayoutContext<'a> {
     }
 }
 
-impl<'a> ElementStateContext for LayoutContext<'a> {
-    fn current_view_id(&self) -> usize {
-        *self.view_stack.last().unwrap()
-    }
-}
-
 pub struct PaintContext<'a> {
     rendered_views: &'a mut HashMap<usize, ElementBox>,
+    view_stack: Vec<usize>,
     pub scene: &'a mut Scene,
     pub font_cache: &'a FontCache,
     pub text_layout_cache: &'a TextLayoutCache,
@@ -365,10 +578,16 @@ pub struct PaintContext<'a> {
 impl<'a> PaintContext<'a> {
     fn paint(&mut self, view_id: usize, origin: Vector2F, visible_bounds: RectF) {
         if let Some(mut tree) = self.rendered_views.remove(&view_id) {
+            self.view_stack.push(view_id);
             tree.paint(origin, visible_bounds, self);
             self.rendered_views.insert(view_id, tree);
+            self.view_stack.pop();
         }
     }
+
+    pub fn current_view_id(&self) -> usize {
+        *self.view_stack.last().unwrap()
+    }
 }
 
 impl<'a> Deref for PaintContext<'a> {
@@ -393,9 +612,8 @@ pub struct EventContext<'a> {
 impl<'a> EventContext<'a> {
     fn dispatch_event(&mut self, view_id: usize, event: &Event) -> bool {
         if let Some(mut element) = self.rendered_views.remove(&view_id) {
-            self.view_stack.push(view_id);
+            let result =
-            let result = element.dispatch_event(event, self);
+                self.with_current_view(view_id, |this| element.dispatch_event(event, this));
-            self.view_stack.pop();
             self.rendered_views.insert(view_id, element);
             result
         } else {
@@ -403,9 +621,19 @@ impl<'a> EventContext<'a> {
         }
     }
 
+    fn with_current_view<F, T>(&mut self, view_id: usize, f: F) -> T
+    where
+        F: FnOnce(&mut Self) -> T,
+    {
+        self.view_stack.push(view_id);
+        let result = f(self);
+        self.view_stack.pop();
+        result
+    }
+
     pub fn dispatch_any_action(&mut self, action: Box<dyn Action>) {
         self.dispatched_actions.push(DispatchDirective {
-            path: self.view_stack.clone(),
+            dispatcher_view_id: self.view_stack.last().copied(),
             action,
         });
     }

crates/gpui/src/scene.rs

@@ -1,6 +1,6 @@
 use serde::Deserialize;
 use serde_json::json;
-use std::{borrow::Cow, sync::Arc};
+use std::{any::TypeId, borrow::Cow, rc::Rc, sync::Arc};
 
 use crate::{
     color::Color,
@@ -8,7 +8,7 @@ use crate::{
     geometry::{rect::RectF, vector::Vector2F},
     json::ToJson,
     platform::CursorStyle,
-    ImageData,
+    EventContext, ImageData,
 };
 
 pub struct Scene {
@@ -33,7 +33,35 @@ pub struct Layer {
     image_glyphs: Vec<ImageGlyph>,
     icons: Vec<Icon>,
     paths: Vec<Path>,
-    cursor_styles: Vec<(RectF, CursorStyle)>,
+    cursor_regions: Vec<CursorRegion>,
+    mouse_regions: Vec<MouseRegion>,
+}
+
+#[derive(Copy, Clone)]
+pub struct CursorRegion {
+    pub bounds: RectF,
+    pub style: CursorStyle,
+}
+
+#[derive(Clone)]
+pub struct MouseRegion {
+    pub view_id: usize,
+    pub tag: TypeId,
+    pub region_id: usize,
+    pub bounds: RectF,
+    pub hover: Option<Rc<dyn Fn(bool, &mut EventContext)>>,
+    pub mouse_down: Option<Rc<dyn Fn(Vector2F, &mut EventContext)>>,
+    pub click: Option<Rc<dyn Fn(Vector2F, usize, &mut EventContext)>>,
+    pub right_mouse_down: Option<Rc<dyn Fn(Vector2F, &mut EventContext)>>,
+    pub right_click: Option<Rc<dyn Fn(Vector2F, usize, &mut EventContext)>>,
+    pub drag: Option<Rc<dyn Fn(Vector2F, &mut EventContext)>>,
+}
+
+#[derive(Copy, Clone, Eq, PartialEq, Hash)]
+pub struct MouseRegionId {
+    pub view_id: usize,
+    pub tag: TypeId,
+    pub region_id: usize,
 }
 
 #[derive(Default, Debug)]
@@ -175,13 +203,20 @@ impl Scene {
         self.stacking_contexts.iter().flat_map(|s| &s.layers)
     }
 
-    pub fn cursor_styles(&self) -> Vec<(RectF, CursorStyle)> {
+    pub fn cursor_regions(&self) -> Vec<CursorRegion> {
         self.layers()
-            .flat_map(|layer| &layer.cursor_styles)
+            .flat_map(|layer| &layer.cursor_regions)
             .copied()
             .collect()
     }
 
+    pub fn mouse_regions(&self) -> Vec<MouseRegion> {
+        self.layers()
+            .flat_map(|layer| &layer.mouse_regions)
+            .cloned()
+            .collect()
+    }
+
     pub fn push_stacking_context(&mut self, clip_bounds: Option<RectF>) {
         self.active_stacking_context_stack
             .push(self.stacking_contexts.len());
@@ -206,8 +241,12 @@ impl Scene {
         self.active_layer().push_quad(quad)
     }
 
-    pub fn push_cursor_style(&mut self, bounds: RectF, style: CursorStyle) {
+    pub fn push_cursor_region(&mut self, region: CursorRegion) {
-        self.active_layer().push_cursor_style(bounds, style);
+        self.active_layer().push_cursor_region(region);
+    }
+
+    pub fn push_mouse_region(&mut self, region: MouseRegion) {
+        self.active_layer().push_mouse_region(region);
     }
 
     pub fn push_image(&mut self, image: Image) {
@@ -298,7 +337,8 @@ impl Layer {
             glyphs: Default::default(),
             icons: Default::default(),
             paths: Default::default(),
-            cursor_styles: Default::default(),
+            cursor_regions: Default::default(),
+            mouse_regions: Default::default(),
         }
     }
 
@@ -316,10 +356,24 @@ impl Layer {
         self.quads.as_slice()
     }
 
-    fn push_cursor_style(&mut self, bounds: RectF, style: CursorStyle) {
+    fn push_cursor_region(&mut self, region: CursorRegion) {
-        if let Some(bounds) = bounds.intersection(self.clip_bounds.unwrap_or(bounds)) {
+        if let Some(bounds) = region
+            .bounds
+            .intersection(self.clip_bounds.unwrap_or(region.bounds))
+        {
             if can_draw(bounds) {
-                self.cursor_styles.push((bounds, style));
+                self.cursor_regions.push(region);
+            }
+        }
+    }
+
+    fn push_mouse_region(&mut self, region: MouseRegion) {
+        if let Some(bounds) = region
+            .bounds
+            .intersection(self.clip_bounds.unwrap_or(region.bounds))
+        {
+            if can_draw(bounds) {
+                self.mouse_regions.push(region);
             }
         }
     }
@@ -484,6 +538,16 @@ impl ToJson for Border {
     }
 }
 
+impl MouseRegion {
+    pub fn id(&self) -> MouseRegionId {
+        MouseRegionId {
+            view_id: self.view_id,
+            tag: self.tag,
+            region_id: self.region_id,
+        }
+    }
+}
+
 fn can_draw(bounds: RectF) -> bool {
     let size = bounds.size();
     size.x() > 0. && size.y() > 0.

crates/gpui/src/views/select.rs

@@ -123,7 +123,6 @@ impl View for Select {
             .boxed(),
         );
         if self.is_open {
-            let handle = self.handle.clone();
             result.add_child(
                 Overlay::new(
                     Container::new(
@@ -131,9 +130,8 @@ impl View for Select {
                             UniformList::new(
                                 self.list_state.clone(),
                                 self.item_count,
-                                move |mut range, items, cx| {
+                                cx,
-                                    let handle = handle.upgrade(cx).unwrap();
+                                move |this, mut range, items, cx| {
-                                    let this = handle.read(cx);
                                     let selected_item_ix = this.selected_item_ix;
                                     range.end = range.end.min(this.item_count);
                                     items.extend(range.map(|ix| {
@@ -141,7 +139,7 @@ impl View for Select {
                                             ix,
                                             cx,
                                             |mouse_state, cx| {
-                                                (handle.read(cx).render_item)(
+                                                (this.render_item)(
                                                     ix,
                                                     if ix == selected_item_ix {
                                                         ItemType::Selected

crates/outline/src/outline.rs

@@ -4,8 +4,8 @@ use editor::{
 };
 use fuzzy::StringMatch;
 use gpui::{
-    actions, elements::*, geometry::vector::Vector2F, AppContext, Entity, MutableAppContext,
+    actions, elements::*, geometry::vector::Vector2F, AppContext, Entity, MouseState,
-    RenderContext, Task, View, ViewContext, ViewHandle,
+    MutableAppContext, RenderContext, Task, View, ViewContext, ViewHandle,
 };
 use language::Outline;
 use ordered_float::OrderedFloat;
@@ -231,7 +231,7 @@ impl PickerDelegate for OutlineView {
     fn render_match(
         &self,
         ix: usize,
-        mouse_state: &MouseState,
+        mouse_state: MouseState,
         selected: bool,
         cx: &AppContext,
     ) -> ElementBox {

crates/picker/src/picker.rs

@@ -1,14 +1,14 @@
 use editor::Editor;
 use gpui::{
     elements::{
-        ChildView, Flex, Label, MouseEventHandler, MouseState, ParentElement, ScrollTarget,
+        ChildView, Flex, Label, MouseEventHandler, ParentElement, ScrollTarget, UniformList,
-        UniformList, UniformListState,
+        UniformListState,
     },
     geometry::vector::{vec2f, Vector2F},
     keymap,
     platform::CursorStyle,
-    AppContext, Axis, Element, ElementBox, Entity, MutableAppContext, RenderContext, Task, View,
+    AppContext, Axis, Element, ElementBox, Entity, MouseState, MutableAppContext, RenderContext,
-    ViewContext, ViewHandle, WeakViewHandle,
+    Task, View, ViewContext, ViewHandle, WeakViewHandle,
 };
 use menu::{Cancel, Confirm, SelectFirst, SelectIndex, SelectLast, SelectNext, SelectPrev};
 use settings::Settings;
@@ -32,7 +32,7 @@ pub trait PickerDelegate: View {
     fn render_match(
         &self,
         ix: usize,
-        state: &MouseState,
+        state: MouseState,
         selected: bool,
         cx: &AppContext,
     ) -> ElementBox;
@@ -52,6 +52,7 @@ impl<D: PickerDelegate> View for Picker<D> {
 
     fn render(&mut self, cx: &mut RenderContext<Self>) -> gpui::ElementBox {
         let settings = cx.global::<Settings>();
+        let container_style = settings.theme.picker.container;
         let delegate = self.delegate.clone();
         let match_count = if let Some(delegate) = delegate.upgrade(cx.app) {
             delegate.read(cx).match_count()
@@ -78,8 +79,9 @@ impl<D: PickerDelegate> View for Picker<D> {
                     UniformList::new(
                         self.list_state.clone(),
                         match_count,
-                        move |mut range, items, cx| {
+                        cx,
-                            let delegate = delegate.upgrade(cx).unwrap();
+                        move |this, mut range, items, cx| {
+                            let delegate = this.delegate.upgrade(cx).unwrap();
                             let selected_ix = delegate.read(cx).selected_index();
                             range.end = cmp::min(range.end, delegate.read(cx).match_count());
                             items.extend(range.map(move |ix| {
@@ -101,7 +103,7 @@ impl<D: PickerDelegate> View for Picker<D> {
                 .boxed(),
             )
             .contained()
-            .with_style(settings.theme.picker.container)
+            .with_style(container_style)
             .constrained()
             .with_max_width(self.max_size.x())
             .with_max_height(self.max_size.y())

crates/project_panel/src/project_panel.rs

@@ -12,7 +12,7 @@ use gpui::{
     impl_internal_actions, keymap,
     platform::CursorStyle,
     AppContext, ClipboardItem, Element, ElementBox, Entity, ModelHandle, MutableAppContext,
-    PromptLevel, Task, View, ViewContext, ViewHandle, WeakViewHandle,
+    PromptLevel, RenderContext, Task, View, ViewContext, ViewHandle, WeakViewHandle,
 };
 use menu::{Confirm, SelectNext, SelectPrev};
 use project::{Entry, EntryKind, Project, ProjectEntryId, ProjectPath, Worktree, WorktreeId};
@@ -795,8 +795,8 @@ impl ProjectPanel {
     fn for_each_visible_entry(
         &self,
         range: Range<usize>,
-        cx: &mut ViewContext<ProjectPanel>,
+        cx: &mut RenderContext<ProjectPanel>,
-        mut callback: impl FnMut(ProjectEntryId, EntryDetails, &mut ViewContext<ProjectPanel>),
+        mut callback: impl FnMut(ProjectEntryId, EntryDetails, &mut RenderContext<ProjectPanel>),
     ) {
         let mut ix = 0;
         for (worktree_id, visible_worktree_entries) in &self.visible_entries {
@@ -869,7 +869,7 @@ impl ProjectPanel {
         details: EntryDetails,
         editor: &ViewHandle<Editor>,
         theme: &theme::ProjectPanel,
-        cx: &mut ViewContext<Self>,
+        cx: &mut RenderContext<Self>,
     ) -> ElementBox {
         let kind = details.kind;
         let show_editor = details.is_editing && !details.is_processing;
@@ -961,24 +961,19 @@ impl View for ProjectPanel {
         let theme = &cx.global::<Settings>().theme.project_panel;
         let mut container_style = theme.container;
         let padding = std::mem::take(&mut container_style.padding);
-        let handle = self.handle.clone();
         Stack::new()
             .with_child(
-                MouseEventHandler::new::<Tag, _, _>(0, cx, |_, _| {
+                MouseEventHandler::new::<Tag, _, _>(0, cx, |_, cx| {
                     UniformList::new(
                         self.list.clone(),
                         self.visible_entries
                             .iter()
                             .map(|(_, worktree_entries)| worktree_entries.len())
                             .sum(),
-                        move |range, items, cx| {
-                            let theme = cx.global::<Settings>().theme.clone();
-                            let this = handle.upgrade(cx).unwrap();
-                            this.update(cx.app, |this, cx| {
-                                this.for_each_visible_entry(
-                                    range.clone(),
                         cx,
-                                    |id, details, cx| {
+                        move |this, range, items, cx| {
+                            let theme = cx.global::<Settings>().theme.clone();
+                            this.for_each_visible_entry(range.clone(), cx, |id, details, cx| {
                                 items.push(Self::render_entry(
                                     id,
                                     details,
@@ -986,9 +981,7 @@ impl View for ProjectPanel {
                                     &theme.project_panel,
                                     cx,
                                 ));
-                                    },
+                            });
-                                );
-                            })
                         },
                     )
                     .with_padding_top(padding.top)
@@ -1458,7 +1451,7 @@ mod tests {
         let mut result = Vec::new();
         let mut project_entries = HashSet::new();
         let mut has_editor = false;
-        panel.update(cx, |panel, cx| {
+        cx.render(panel, |panel, cx| {
             panel.for_each_visible_entry(range, cx, |project_entry, details, _| {
                 if details.is_editing {
                     assert!(!has_editor, "duplicate editor entry");

crates/project_symbols/src/project_symbols.rs

@@ -3,8 +3,8 @@ use editor::{
 };
 use fuzzy::{StringMatch, StringMatchCandidate};
 use gpui::{
-    actions, elements::*, AppContext, Entity, ModelHandle, MutableAppContext, RenderContext, Task,
+    actions, elements::*, AppContext, Entity, ModelHandle, MouseState, MutableAppContext,
-    View, ViewContext, ViewHandle,
+    RenderContext, Task, View, ViewContext, ViewHandle,
 };
 use ordered_float::OrderedFloat;
 use picker::{Picker, PickerDelegate};
@@ -221,7 +221,7 @@ impl PickerDelegate for ProjectSymbolsView {
     fn render_match(
         &self,
         ix: usize,
-        mouse_state: &MouseState,
+        mouse_state: MouseState,
         selected: bool,
         cx: &AppContext,
     ) -> ElementBox {

crates/theme/src/theme.rs

@@ -2,9 +2,9 @@ mod theme_registry;
 
 use gpui::{
     color::Color,
-    elements::{ContainerStyle, ImageStyle, LabelStyle, MouseState},
+    elements::{ContainerStyle, ImageStyle, LabelStyle},
     fonts::{HighlightStyle, TextStyle},
-    Border,
+    Border, MouseState,
 };
 use serde::{de::DeserializeOwned, Deserialize};
 use serde_json::Value;
@@ -505,7 +505,7 @@ pub struct Interactive<T> {
 }
 
 impl<T> Interactive<T> {
-    pub fn style_for(&self, state: &MouseState, active: bool) -> &T {
+    pub fn style_for(&self, state: MouseState, active: bool) -> &T {
         if active {
             if state.hovered {
                 self.active_hover

crates/theme_selector/src/theme_selector.rs

@@ -1,6 +1,6 @@
 use fuzzy::{match_strings, StringMatch, StringMatchCandidate};
 use gpui::{
-    actions, elements::*, AppContext, Element, ElementBox, Entity, MutableAppContext,
+    actions, elements::*, AppContext, Element, ElementBox, Entity, MouseState, MutableAppContext,
     RenderContext, View, ViewContext, ViewHandle,
 };
 use picker::{Picker, PickerDelegate};
@@ -213,7 +213,7 @@ impl PickerDelegate for ThemeSelector {
     fn render_match(
         &self,
         ix: usize,
-        mouse_state: &MouseState,
+        mouse_state: MouseState,
         selected: bool,
         cx: &AppContext,
     ) -> ElementBox {

crates/workspace/src/pane.rs

@@ -689,6 +689,7 @@ impl Pane {
         let theme = cx.global::<Settings>().theme.clone();
 
         enum Tabs {}
+        enum Tab {}
         let pane = cx.handle();
         let tabs = MouseEventHandler::new::<Tabs, _, _>(0, cx, |mouse_state, cx| {
             let autoscroll = if mem::take(&mut self.autoscroll) {
@@ -717,7 +718,7 @@ impl Pane {
                         style.container.border.left = false;
                     }
 
-                    EventHandler::new(
+                    MouseEventHandler::new::<Tab, _, _>(ix, cx, |_, cx| {
                         Container::new(
                             Flex::row()
                                 .with_child(
@@ -807,11 +808,10 @@ impl Pane {
                                 .boxed(),
                         )
                         .with_style(style.container)
-                        .boxed(),
+                        .boxed()
-                    )
+                    })
-                    .on_mouse_down(move |cx| {
+                    .on_mouse_down(move |_, cx| {
                         cx.dispatch_action(ActivateItem(ix));
-                        true
                     })
                     .boxed()
                 })

crates/workspace/src/sidebar.rs

@@ -165,6 +165,7 @@ impl Sidebar {
             ..Default::default()
         })
         .with_cursor_style(CursorStyle::ResizeLeftRight)
+        .on_mouse_down(|_, _| {}) // This prevents the mouse down event from being propagated elsewhere
         .on_drag(move |delta, cx| {
             let prev_width = *actual_width.borrow();
             *custom_width.borrow_mut() = 0f32