diff --git a/crates/gpui/src/presenter.rs b/crates/gpui/src/presenter.rs
index 243863149d..a2b3230190 100644
--- a/crates/gpui/src/presenter.rs
+++ b/crates/gpui/src/presenter.rs
@@ -252,7 +252,6 @@ impl Presenter {
                         } else if let Some(handler) = region
                             .handlers
                             .get(&(MouseRegionEvent::down_out_disc(), Some(*button)))
-                            .cloned()
                         {
                             mouse_down_out_handlers.push((
                                 handler,
diff --git a/crates/gpui/src/scene.rs b/crates/gpui/src/scene.rs
index f5577c5e5d..a1f12b76d3 100644
--- a/crates/gpui/src/scene.rs
+++ b/crates/gpui/src/scene.rs
@@ -1,7 +1,8 @@
-use collections::HashMap;
+mod mouse_region;
+
 use serde::Deserialize;
 use serde_json::json;
-use std::{any::TypeId, borrow::Cow, mem::Discriminant, rc::Rc, sync::Arc};
+use std::{borrow::Cow, sync::Arc};
 
 use crate::{
     color::Color,
@@ -9,8 +10,9 @@ use crate::{
     geometry::{rect::RectF, vector::Vector2F},
     json::ToJson,
     platform::CursorStyle,
-    EventContext, ImageData, MouseButton, MouseButtonEvent, MouseMovedEvent, ScrollWheelEvent,
+    ImageData,
 };
+pub use mouse_region::*;
 
 pub struct Scene {
     scale_factor: f32,
@@ -45,255 +47,6 @@ pub struct CursorRegion {
     pub style: CursorStyle,
 }
 
-#[derive(Debug)]
-pub enum MouseRegionEvent {
-    Move(MouseMovedEvent),
-    Drag(Vector2F, MouseMovedEvent),
-    Hover(bool, MouseMovedEvent),
-    Down(MouseButtonEvent),
-    Up(MouseButtonEvent),
-    Click(MouseButtonEvent),
-    DownOut(MouseButtonEvent),
-    ScrollWheel(ScrollWheelEvent),
-}
-
-impl MouseRegionEvent {
-    pub fn move_disc() -> Discriminant<MouseRegionEvent> {
-        std::mem::discriminant(&MouseRegionEvent::Move(Default::default()))
-    }
-    pub fn drag_disc() -> Discriminant<MouseRegionEvent> {
-        std::mem::discriminant(&MouseRegionEvent::Drag(
-            Default::default(),
-            Default::default(),
-        ))
-    }
-    pub fn hover_disc() -> Discriminant<MouseRegionEvent> {
-        std::mem::discriminant(&MouseRegionEvent::Hover(
-            Default::default(),
-            Default::default(),
-        ))
-    }
-    pub fn down_disc() -> Discriminant<MouseRegionEvent> {
-        std::mem::discriminant(&MouseRegionEvent::Down(Default::default()))
-    }
-    pub fn up_disc() -> Discriminant<MouseRegionEvent> {
-        std::mem::discriminant(&MouseRegionEvent::Up(Default::default()))
-    }
-    pub fn click_disc() -> Discriminant<MouseRegionEvent> {
-        std::mem::discriminant(&MouseRegionEvent::Click(Default::default()))
-    }
-    pub fn down_out_disc() -> Discriminant<MouseRegionEvent> {
-        std::mem::discriminant(&MouseRegionEvent::DownOut(Default::default()))
-    }
-    pub fn scroll_wheel_disc() -> Discriminant<MouseRegionEvent> {
-        std::mem::discriminant(&MouseRegionEvent::ScrollWheel(Default::default()))
-    }
-
-    pub fn handler_key(&self) -> (Discriminant<MouseRegionEvent>, Option<MouseButton>) {
-        match self {
-            MouseRegionEvent::Move(_) => (Self::move_disc(), None),
-            MouseRegionEvent::Drag(_, MouseMovedEvent { pressed_button, .. }) => {
-                (Self::drag_disc(), *pressed_button)
-            }
-            MouseRegionEvent::Hover(_, _) => (Self::hover_disc(), None),
-            MouseRegionEvent::Down(MouseButtonEvent { button, .. }) => {
-                (Self::down_disc(), Some(*button))
-            }
-            MouseRegionEvent::Up(MouseButtonEvent { button, .. }) => {
-                (Self::up_disc(), Some(*button))
-            }
-            MouseRegionEvent::Click(MouseButtonEvent { button, .. }) => {
-                (Self::click_disc(), Some(*button))
-            }
-            MouseRegionEvent::DownOut(MouseButtonEvent { button, .. }) => {
-                (Self::down_out_disc(), Some(*button))
-            }
-            MouseRegionEvent::ScrollWheel(_) => (Self::scroll_wheel_disc(), None),
-        }
-    }
-}
-
-#[derive(Clone, Default)]
-pub struct MouseRegion {
-    pub view_id: usize,
-    pub discriminant: Option<(TypeId, usize)>,
-    pub bounds: RectF,
-    pub handlers: HashMap<
-        (Discriminant<MouseRegionEvent>, Option<MouseButton>),
-        Rc<dyn Fn(MouseRegionEvent, &mut EventContext)>,
-    >,
-}
-
-impl MouseRegion {
-    pub fn new(view_id: usize, discriminant: Option<(TypeId, usize)>, bounds: RectF) -> Self {
-        Self {
-            view_id,
-            discriminant,
-            bounds,
-            handlers: Default::default(),
-        }
-    }
-
-    pub fn handle_all(
-        view_id: usize,
-        discriminant: Option<(TypeId, usize)>,
-        bounds: RectF,
-    ) -> Self {
-        let mut handlers: HashMap<
-            (Discriminant<MouseRegionEvent>, Option<MouseButton>),
-            Rc<dyn Fn(MouseRegionEvent, &mut EventContext)>,
-        > = Default::default();
-        handlers.insert((MouseRegionEvent::move_disc(), None), Rc::new(|_, _| {}));
-        handlers.insert((MouseRegionEvent::hover_disc(), None), Rc::new(|_, _| {}));
-        for button in MouseButton::all() {
-            handlers.insert(
-                (MouseRegionEvent::drag_disc(), Some(button)),
-                Rc::new(|_, _| {}),
-            );
-            handlers.insert(
-                (MouseRegionEvent::down_disc(), Some(button)),
-                Rc::new(|_, _| {}),
-            );
-            handlers.insert(
-                (MouseRegionEvent::up_disc(), Some(button)),
-                Rc::new(|_, _| {}),
-            );
-            handlers.insert(
-                (MouseRegionEvent::click_disc(), Some(button)),
-                Rc::new(|_, _| {}),
-            );
-            handlers.insert(
-                (MouseRegionEvent::down_out_disc(), Some(button)),
-                Rc::new(|_, _| {}),
-            );
-        }
-        handlers.insert(
-            (MouseRegionEvent::scroll_wheel_disc(), None),
-            Rc::new(|_, _| {}),
-        );
-
-        Self {
-            view_id,
-            discriminant,
-            bounds,
-            handlers,
-        }
-    }
-
-    pub fn on_down(
-        mut self,
-        button: MouseButton,
-        handler: impl Fn(MouseButtonEvent, &mut EventContext) + 'static,
-    ) -> Self {
-        self.handlers.insert((MouseRegionEvent::down_disc(), Some(button)),
-            Rc::new(move |region_event, cx| {
-                if let MouseRegionEvent::Down(mouse_button_event) = region_event {
-                    handler(mouse_button_event, cx);
-                } else {
-                    panic!(
-                        "Mouse Region Event incorrectly called with mismatched event type. Expected MouseRegionEvent::Down, found {:?}", 
-                        region_event);
-                }
-            }));
-        self
-    }
-
-    pub fn on_up(
-        mut self,
-        button: MouseButton,
-        handler: impl Fn(MouseButtonEvent, &mut EventContext) + 'static,
-    ) -> Self {
-        self.handlers.insert((MouseRegionEvent::up_disc(), Some(button)),
-            Rc::new(move |region_event, cx| {
-                if let MouseRegionEvent::Up(mouse_button_event) = region_event {
-                    handler(mouse_button_event, cx);
-                } else {
-                    panic!(
-                        "Mouse Region Event incorrectly called with mismatched event type. Expected MouseRegionEvent::Up, found {:?}", 
-                        region_event);
-                }
-            }));
-        self
-    }
-
-    pub fn on_click(
-        mut self,
-        button: MouseButton,
-        handler: impl Fn(MouseButtonEvent, &mut EventContext) + 'static,
-    ) -> Self {
-        self.handlers.insert((MouseRegionEvent::click_disc(), Some(button)),
-            Rc::new(move |region_event, cx| {
-                if let MouseRegionEvent::Click(mouse_button_event) = region_event {
-                    handler(mouse_button_event, cx);
-                } else {
-                    panic!(
-                        "Mouse Region Event incorrectly called with mismatched event type. Expected MouseRegionEvent::Click, found {:?}", 
-                        region_event);
-                }
-            }));
-        self
-    }
-
-    pub fn on_down_out(
-        mut self,
-        button: MouseButton,
-        handler: impl Fn(MouseButtonEvent, &mut EventContext) + 'static,
-    ) -> Self {
-        self.handlers.insert((MouseRegionEvent::down_out_disc(), Some(button)),
-            Rc::new(move |region_event, cx| {
-                if let MouseRegionEvent::DownOut(mouse_button_event) = region_event {
-                    handler(mouse_button_event, cx);
-                } else {
-                    panic!(
-                        "Mouse Region Event incorrectly called with mismatched event type. Expected MouseRegionEvent::DownOut, found {:?}", 
-                        region_event);
-                }
-            }));
-        self
-    }
-
-    pub fn on_drag(
-        mut self,
-        button: MouseButton,
-        handler: impl Fn(Vector2F, MouseMovedEvent, &mut EventContext) + 'static,
-    ) -> Self {
-        self.handlers.insert((MouseRegionEvent::drag_disc(), Some(button)),
-            Rc::new(move |region_event, cx| {
-                if let MouseRegionEvent::Drag(prev_drag_position, mouse_moved_event) = region_event {
-                    handler(prev_drag_position, mouse_moved_event, cx);
-                } else {
-                    panic!(
-                        "Mouse Region Event incorrectly called with mismatched event type. Expected MouseRegionEvent::Drag, found {:?}", 
-                        region_event);
-                }
-            }));
-        self
-    }
-
-    pub fn on_hover(
-        mut self,
-        handler: impl Fn(bool, MouseMovedEvent, &mut EventContext) + 'static,
-    ) -> Self {
-        self.handlers.insert((MouseRegionEvent::hover_disc(), None),
-            Rc::new(move |region_event, cx| {
-                if let MouseRegionEvent::Hover(hover, mouse_moved_event) = region_event {
-                    handler(hover, mouse_moved_event, cx);
-                } else {
-                    panic!(
-                        "Mouse Region Event incorrectly called with mismatched event type. Expected MouseRegionEvent::Hover, found {:?}", 
-                        region_event);
-                }
-            }));
-        self
-    }
-}
-
-#[derive(Copy, Clone, Eq, PartialEq, Hash)]
-pub struct MouseRegionId {
-    pub view_id: usize,
-    pub discriminant: (TypeId, usize),
-}
-
 #[derive(Default, Debug)]
 pub struct Quad {
     pub bounds: RectF,
diff --git a/crates/gpui/src/scene/mouse_region.rs b/crates/gpui/src/scene/mouse_region.rs
new file mode 100644
index 0000000000..3d680876c7
--- /dev/null
+++ b/crates/gpui/src/scene/mouse_region.rs
@@ -0,0 +1,327 @@
+use std::{any::TypeId, mem::Discriminant, rc::Rc};
+
+use collections::HashMap;
+use pathfinder_geometry::{rect::RectF, vector::Vector2F};
+
+use crate::{EventContext, MouseButton, MouseButtonEvent, MouseMovedEvent, ScrollWheelEvent};
+
+#[derive(Clone, Default)]
+pub struct MouseRegion {
+    pub view_id: usize,
+    pub discriminant: Option<(TypeId, usize)>,
+    pub bounds: RectF,
+    pub handlers: HandlerSet,
+}
+
+impl MouseRegion {
+    pub fn new(view_id: usize, discriminant: Option<(TypeId, usize)>, bounds: RectF) -> Self {
+        Self {
+            view_id,
+            discriminant,
+            bounds,
+            handlers: Default::default(),
+        }
+    }
+
+    pub fn handle_all(
+        view_id: usize,
+        discriminant: Option<(TypeId, usize)>,
+        bounds: RectF,
+    ) -> Self {
+        Self {
+            view_id,
+            discriminant,
+            bounds,
+            handlers: HandlerSet::handle_all(),
+        }
+    }
+
+    pub fn on_down(
+        mut self,
+        button: MouseButton,
+        handler: impl Fn(MouseButtonEvent, &mut EventContext) + 'static,
+    ) -> Self {
+        self.handlers = self.handlers.on_down(button, handler);
+        self
+    }
+
+    pub fn on_up(
+        mut self,
+        button: MouseButton,
+        handler: impl Fn(MouseButtonEvent, &mut EventContext) + 'static,
+    ) -> Self {
+        self.handlers = self.handlers.on_up(button, handler);
+        self
+    }
+
+    pub fn on_click(
+        mut self,
+        button: MouseButton,
+        handler: impl Fn(MouseButtonEvent, &mut EventContext) + 'static,
+    ) -> Self {
+        self.handlers = self.handlers.on_click(button, handler);
+        self
+    }
+
+    pub fn on_down_out(
+        mut self,
+        button: MouseButton,
+        handler: impl Fn(MouseButtonEvent, &mut EventContext) + 'static,
+    ) -> Self {
+        self.handlers = self.handlers.on_down_out(button, handler);
+        self
+    }
+
+    pub fn on_drag(
+        mut self,
+        button: MouseButton,
+        handler: impl Fn(Vector2F, MouseMovedEvent, &mut EventContext) + 'static,
+    ) -> Self {
+        self.handlers = self.handlers.on_drag(button, handler);
+        self
+    }
+
+    pub fn on_hover(
+        mut self,
+        handler: impl Fn(bool, MouseMovedEvent, &mut EventContext) + 'static,
+    ) -> Self {
+        self.handlers = self.handlers.on_hover(handler);
+        self
+    }
+}
+
+#[derive(Copy, Clone, Eq, PartialEq, Hash)]
+pub struct MouseRegionId {
+    pub view_id: usize,
+    pub discriminant: (TypeId, usize),
+}
+
+#[derive(Clone, Default)]
+pub struct HandlerSet {
+    pub set: HashMap<
+        (Discriminant<MouseRegionEvent>, Option<MouseButton>),
+        Rc<dyn Fn(MouseRegionEvent, &mut EventContext)>,
+    >,
+}
+
+impl HandlerSet {
+    pub fn handle_all() -> Self {
+        let mut set: HashMap<
+            (Discriminant<MouseRegionEvent>, Option<MouseButton>),
+            Rc<dyn Fn(MouseRegionEvent, &mut EventContext)>,
+        > = Default::default();
+
+        set.insert((MouseRegionEvent::move_disc(), None), Rc::new(|_, _| {}));
+        set.insert((MouseRegionEvent::hover_disc(), None), Rc::new(|_, _| {}));
+        for button in MouseButton::all() {
+            set.insert(
+                (MouseRegionEvent::drag_disc(), Some(button)),
+                Rc::new(|_, _| {}),
+            );
+            set.insert(
+                (MouseRegionEvent::down_disc(), Some(button)),
+                Rc::new(|_, _| {}),
+            );
+            set.insert(
+                (MouseRegionEvent::up_disc(), Some(button)),
+                Rc::new(|_, _| {}),
+            );
+            set.insert(
+                (MouseRegionEvent::click_disc(), Some(button)),
+                Rc::new(|_, _| {}),
+            );
+            set.insert(
+                (MouseRegionEvent::down_out_disc(), Some(button)),
+                Rc::new(|_, _| {}),
+            );
+        }
+        set.insert(
+            (MouseRegionEvent::scroll_wheel_disc(), None),
+            Rc::new(|_, _| {}),
+        );
+
+        HandlerSet { set }
+    }
+
+    pub fn get(
+        &self,
+        key: &(Discriminant<MouseRegionEvent>, Option<MouseButton>),
+    ) -> Option<Rc<dyn Fn(MouseRegionEvent, &mut EventContext)>> {
+        self.set.get(key).cloned()
+    }
+
+    pub fn on_down(
+        mut self,
+        button: MouseButton,
+        handler: impl Fn(MouseButtonEvent, &mut EventContext) + 'static,
+    ) -> Self {
+        self.set.insert((MouseRegionEvent::down_disc(), Some(button)),
+            Rc::new(move |region_event, cx| {
+                if let MouseRegionEvent::Down(mouse_button_event) = region_event {
+                    handler(mouse_button_event, cx);
+                } else {
+                    panic!(
+                        "Mouse Region Event incorrectly called with mismatched event type. Expected MouseRegionEvent::Down, found {:?}", 
+                        region_event);
+                }
+            }));
+        self
+    }
+
+    pub fn on_up(
+        mut self,
+        button: MouseButton,
+        handler: impl Fn(MouseButtonEvent, &mut EventContext) + 'static,
+    ) -> Self {
+        self.set.insert((MouseRegionEvent::up_disc(), Some(button)),
+            Rc::new(move |region_event, cx| {
+                if let MouseRegionEvent::Up(mouse_button_event) = region_event {
+                    handler(mouse_button_event, cx);
+                } else {
+                    panic!(
+                        "Mouse Region Event incorrectly called with mismatched event type. Expected MouseRegionEvent::Up, found {:?}", 
+                        region_event);
+                }
+            }));
+        self
+    }
+
+    pub fn on_click(
+        mut self,
+        button: MouseButton,
+        handler: impl Fn(MouseButtonEvent, &mut EventContext) + 'static,
+    ) -> Self {
+        self.set.insert((MouseRegionEvent::click_disc(), Some(button)),
+            Rc::new(move |region_event, cx| {
+                if let MouseRegionEvent::Click(mouse_button_event) = region_event {
+                    handler(mouse_button_event, cx);
+                } else {
+                    panic!(
+                        "Mouse Region Event incorrectly called with mismatched event type. Expected MouseRegionEvent::Click, found {:?}", 
+                        region_event);
+                }
+            }));
+        self
+    }
+
+    pub fn on_down_out(
+        mut self,
+        button: MouseButton,
+        handler: impl Fn(MouseButtonEvent, &mut EventContext) + 'static,
+    ) -> Self {
+        self.set.insert((MouseRegionEvent::down_out_disc(), Some(button)),
+            Rc::new(move |region_event, cx| {
+                if let MouseRegionEvent::DownOut(mouse_button_event) = region_event {
+                    handler(mouse_button_event, cx);
+                } else {
+                    panic!(
+                        "Mouse Region Event incorrectly called with mismatched event type. Expected MouseRegionEvent::DownOut, found {:?}", 
+                        region_event);
+                }
+            }));
+        self
+    }
+
+    pub fn on_drag(
+        mut self,
+        button: MouseButton,
+        handler: impl Fn(Vector2F, MouseMovedEvent, &mut EventContext) + 'static,
+    ) -> Self {
+        self.set.insert((MouseRegionEvent::drag_disc(), Some(button)),
+            Rc::new(move |region_event, cx| {
+                if let MouseRegionEvent::Drag(prev_drag_position, mouse_moved_event) = region_event {
+                    handler(prev_drag_position, mouse_moved_event, cx);
+                } else {
+                    panic!(
+                        "Mouse Region Event incorrectly called with mismatched event type. Expected MouseRegionEvent::Drag, found {:?}", 
+                        region_event);
+                }
+            }));
+        self
+    }
+
+    pub fn on_hover(
+        mut self,
+        handler: impl Fn(bool, MouseMovedEvent, &mut EventContext) + 'static,
+    ) -> Self {
+        self.set.insert((MouseRegionEvent::hover_disc(), None),
+            Rc::new(move |region_event, cx| {
+                if let MouseRegionEvent::Hover(hover, mouse_moved_event) = region_event {
+                    handler(hover, mouse_moved_event, cx);
+                } else {
+                    panic!(
+                        "Mouse Region Event incorrectly called with mismatched event type. Expected MouseRegionEvent::Hover, found {:?}", 
+                        region_event);
+                }
+            }));
+        self
+    }
+}
+
+#[derive(Debug)]
+pub enum MouseRegionEvent {
+    Move(MouseMovedEvent),
+    Drag(Vector2F, MouseMovedEvent),
+    Hover(bool, MouseMovedEvent),
+    Down(MouseButtonEvent),
+    Up(MouseButtonEvent),
+    Click(MouseButtonEvent),
+    DownOut(MouseButtonEvent),
+    ScrollWheel(ScrollWheelEvent),
+}
+
+impl MouseRegionEvent {
+    pub fn move_disc() -> Discriminant<MouseRegionEvent> {
+        std::mem::discriminant(&MouseRegionEvent::Move(Default::default()))
+    }
+    pub fn drag_disc() -> Discriminant<MouseRegionEvent> {
+        std::mem::discriminant(&MouseRegionEvent::Drag(
+            Default::default(),
+            Default::default(),
+        ))
+    }
+    pub fn hover_disc() -> Discriminant<MouseRegionEvent> {
+        std::mem::discriminant(&MouseRegionEvent::Hover(
+            Default::default(),
+            Default::default(),
+        ))
+    }
+    pub fn down_disc() -> Discriminant<MouseRegionEvent> {
+        std::mem::discriminant(&MouseRegionEvent::Down(Default::default()))
+    }
+    pub fn up_disc() -> Discriminant<MouseRegionEvent> {
+        std::mem::discriminant(&MouseRegionEvent::Up(Default::default()))
+    }
+    pub fn click_disc() -> Discriminant<MouseRegionEvent> {
+        std::mem::discriminant(&MouseRegionEvent::Click(Default::default()))
+    }
+    pub fn down_out_disc() -> Discriminant<MouseRegionEvent> {
+        std::mem::discriminant(&MouseRegionEvent::DownOut(Default::default()))
+    }
+    pub fn scroll_wheel_disc() -> Discriminant<MouseRegionEvent> {
+        std::mem::discriminant(&MouseRegionEvent::ScrollWheel(Default::default()))
+    }
+
+    pub fn handler_key(&self) -> (Discriminant<MouseRegionEvent>, Option<MouseButton>) {
+        match self {
+            MouseRegionEvent::Move(_) => (Self::move_disc(), None),
+            MouseRegionEvent::Drag(_, MouseMovedEvent { pressed_button, .. }) => {
+                (Self::drag_disc(), *pressed_button)
+            }
+            MouseRegionEvent::Hover(_, _) => (Self::hover_disc(), None),
+            MouseRegionEvent::Down(MouseButtonEvent { button, .. }) => {
+                (Self::down_disc(), Some(*button))
+            }
+            MouseRegionEvent::Up(MouseButtonEvent { button, .. }) => {
+                (Self::up_disc(), Some(*button))
+            }
+            MouseRegionEvent::Click(MouseButtonEvent { button, .. }) => {
+                (Self::click_disc(), Some(*button))
+            }
+            MouseRegionEvent::DownOut(MouseButtonEvent { button, .. }) => {
+                (Self::down_out_disc(), Some(*button))
+            }
+            MouseRegionEvent::ScrollWheel(_) => (Self::scroll_wheel_disc(), None),
+        }
+    }
+}