diff --git a/gpui/examples/text.rs b/gpui/examples/text.rs
index 2dad6e0786..df1f367cdb 100644
--- a/gpui/examples/text.rs
+++ b/gpui/examples/text.rs
@@ -10,12 +10,10 @@ use simplelog::SimpleLogger;
 fn main() {
     SimpleLogger::init(LevelFilter::Info, Default::default()).expect("could not initialize logger");
 
-    let app = gpui::App::new(()).unwrap();
-    app.on_finish_launching(|app| {
-        app.platform().activate(true);
-        app.add_window(|_| TextView);
-    })
-    .run();
+    gpui::App::new(()).unwrap().run(|ctx| {
+        ctx.platform().activate(true);
+        ctx.add_window(|_| TextView);
+    });
 }
 
 struct TextView;
diff --git a/gpui/src/app.rs b/gpui/src/app.rs
index ab3f471e73..48720eabcb 100644
--- a/gpui/src/app.rs
+++ b/gpui/src/app.rs
@@ -92,8 +92,8 @@ impl App {
         let platform = platform::test::platform();
         let foreground = Rc::new(executor::Foreground::test());
         let ctx = Rc::new(RefCell::new(MutableAppContext::new(
-            foreground.clone(),
-            Arc::new(platform),
+            foreground,
+            Rc::new(platform),
             asset_source,
         )));
         ctx.borrow_mut().weak_self = Some(Rc::downgrade(&ctx));
@@ -110,7 +110,7 @@ impl App {
         let foreground = Rc::new(executor::Foreground::test());
         let ctx = Rc::new(RefCell::new(MutableAppContext::new(
             foreground.clone(),
-            Arc::new(platform),
+            Rc::new(platform),
             asset_source,
         )));
         let mut ctx_ref = ctx.borrow_mut();
@@ -200,24 +200,19 @@ impl App {
         self
     }
 
-    pub fn on_finish_launching<F>(self, callback: F) -> Self
-    where
-        F: 'static + FnOnce(&mut MutableAppContext),
-    {
-        let ctx = self.0.clone();
-        self.0
-            .borrow()
-            .platform
-            .on_finish_launching(Box::new(move || callback(&mut *ctx.borrow_mut())));
-        self
-    }
-
     pub fn set_menus(&self, menus: &[Menu]) {
         self.0.borrow().platform.set_menus(menus);
     }
 
-    pub fn run(self) {
-        platform::current::run();
+    pub fn run<F>(self, on_finish_launching: F)
+    where
+        F: 'static + FnOnce(&mut MutableAppContext),
+    {
+        let platform = self.platform();
+        platform.run(Box::new(move || {
+            let mut ctx = self.0.borrow_mut();
+            on_finish_launching(&mut *ctx);
+        }))
     }
 
     pub fn on_window_invalidated<F: 'static + FnMut(WindowInvalidation, &mut MutableAppContext)>(
@@ -354,7 +349,7 @@ impl App {
         self.0.borrow().font_cache.clone()
     }
 
-    pub fn platform(&self) -> Arc<dyn platform::Platform> {
+    pub fn platform(&self) -> Rc<dyn platform::Platform> {
         self.0.borrow().platform.clone()
     }
 }
@@ -394,7 +389,7 @@ type GlobalActionCallback = dyn FnMut(&dyn Any, &mut MutableAppContext);
 
 pub struct MutableAppContext {
     weak_self: Option<rc::Weak<RefCell<Self>>>,
-    platform: Arc<dyn platform::Platform>,
+    platform: Rc<dyn platform::Platform>,
     font_cache: Arc<FontCache>,
     assets: Arc<AssetCache>,
     ctx: AppContext,
@@ -422,7 +417,7 @@ pub struct MutableAppContext {
 impl MutableAppContext {
     pub fn new(
         foreground: Rc<executor::Foreground>,
-        platform: Arc<dyn platform::Platform>,
+        platform: Rc<dyn platform::Platform>,
         asset_source: impl AssetSource,
     ) -> Self {
         let fonts = platform.fonts();
@@ -466,7 +461,7 @@ impl MutableAppContext {
         &self.ctx
     }
 
-    pub fn platform(&self) -> Arc<dyn platform::Platform> {
+    pub fn platform(&self) -> Rc<dyn platform::Platform> {
         self.platform.clone()
     }
 
diff --git a/gpui/src/platform/mac/mod.rs b/gpui/src/platform/mac/mod.rs
index 07ada3650a..c2a88c12a4 100644
--- a/gpui/src/platform/mac/mod.rs
+++ b/gpui/src/platform/mac/mod.rs
@@ -12,15 +12,11 @@ use cocoa::base::{BOOL, NO, YES};
 pub use dispatcher::Dispatcher;
 pub use fonts::FontSystem;
 use platform::MacPlatform;
-use std::sync::Arc;
+use std::rc::Rc;
 use window::Window;
 
-pub fn platform() -> Arc<dyn super::Platform> {
-    MacPlatform::new()
-}
-
-pub fn run() {
-    MacPlatform::run();
+pub fn platform() -> Rc<dyn super::Platform> {
+    Rc::new(MacPlatform::new())
 }
 
 trait BoolExt {
diff --git a/gpui/src/platform/mac/platform.rs b/gpui/src/platform/mac/platform.rs
index 40bd3566a5..4201100a6d 100644
--- a/gpui/src/platform/mac/platform.rs
+++ b/gpui/src/platform/mac/platform.rs
@@ -29,7 +29,7 @@ use std::{
     sync::Arc,
 };
 
-const MAC_PLATFORM_IVAR: &'static str = "runner";
+const MAC_PLATFORM_IVAR: &'static str = "platform";
 static mut APP_CLASS: *const Class = ptr::null();
 static mut APP_DELEGATE_CLASS: *const Class = ptr::null();
 
@@ -90,35 +90,12 @@ struct Callbacks {
 }
 
 impl MacPlatform {
-    pub fn new() -> Arc<dyn platform::Platform> {
-        let result = Arc::new(Self {
+    pub fn new() -> Self {
+        Self {
             dispatcher: Arc::new(Dispatcher),
             fonts: Arc::new(FontSystem::new()),
             callbacks: Default::default(),
             menu_item_actions: Default::default(),
-        });
-
-        unsafe {
-            let app: id = msg_send![APP_CLASS, sharedApplication];
-            let app_delegate: id = msg_send![APP_DELEGATE_CLASS, new];
-            let self_ptr = result.as_ref() as *const Self as *const c_void;
-            app.setDelegate_(app_delegate);
-            (*app).set_ivar(MAC_PLATFORM_IVAR, self_ptr);
-            (*app_delegate).set_ivar(MAC_PLATFORM_IVAR, self_ptr);
-        }
-
-        result
-    }
-
-    pub fn run() {
-        unsafe {
-            let pool = NSAutoreleasePool::new(nil);
-            let app: id = msg_send![APP_CLASS, sharedApplication];
-
-            app.run();
-            pool.drain();
-            (*app).set_ivar(MAC_PLATFORM_IVAR, null_mut::<c_void>());
-            (*app.delegate()).set_ivar(MAC_PLATFORM_IVAR, null_mut::<c_void>());
         }
     }
 
@@ -220,8 +197,25 @@ impl platform::Platform for MacPlatform {
         self.callbacks.borrow_mut().open_files = Some(callback);
     }
 
-    fn on_finish_launching(&self, callback: Box<dyn FnOnce() -> ()>) {
-        self.callbacks.borrow_mut().finish_launching = Some(callback);
+    fn run(&self, on_finish_launching: Box<dyn FnOnce() -> ()>) {
+        self.callbacks.borrow_mut().finish_launching = Some(on_finish_launching);
+
+        unsafe {
+            let app: id = msg_send![APP_CLASS, sharedApplication];
+            let app_delegate: id = msg_send![APP_DELEGATE_CLASS, new];
+            app.setDelegate_(app_delegate);
+
+            let self_ptr = self as *const Self as *const c_void;
+            (*app).set_ivar(MAC_PLATFORM_IVAR, self_ptr);
+            (*app_delegate).set_ivar(MAC_PLATFORM_IVAR, self_ptr);
+
+            let pool = NSAutoreleasePool::new(nil);
+            app.run();
+            pool.drain();
+
+            (*app).set_ivar(MAC_PLATFORM_IVAR, null_mut::<c_void>());
+            (*app.delegate()).set_ivar(MAC_PLATFORM_IVAR, null_mut::<c_void>());
+        }
     }
 
     fn dispatcher(&self) -> Arc<dyn platform::Dispatcher> {
diff --git a/gpui/src/platform/mod.rs b/gpui/src/platform/mod.rs
index 6e5d53585f..39825c941e 100644
--- a/gpui/src/platform/mod.rs
+++ b/gpui/src/platform/mod.rs
@@ -28,7 +28,7 @@ pub trait Platform {
     fn on_resign_active(&self, callback: Box<dyn FnMut()>);
     fn on_event(&self, callback: Box<dyn FnMut(Event) -> bool>);
     fn on_open_files(&self, callback: Box<dyn FnMut(Vec<PathBuf>)>);
-    fn on_finish_launching(&self, callback: Box<dyn FnOnce() -> ()>);
+    fn run(&self, on_finish_launching: Box<dyn FnOnce() -> ()>);
 
     fn dispatcher(&self) -> Arc<dyn Dispatcher>;
     fn fonts(&self) -> Arc<dyn FontSystem>;
diff --git a/gpui/src/platform/test.rs b/gpui/src/platform/test.rs
index 1cd4399c1b..b0d19232dc 100644
--- a/gpui/src/platform/test.rs
+++ b/gpui/src/platform/test.rs
@@ -39,7 +39,9 @@ impl super::Platform for Platform {
 
     fn on_open_files(&self, _: Box<dyn FnMut(Vec<std::path::PathBuf>)>) {}
 
-    fn on_finish_launching(&self, _: Box<dyn FnOnce() -> ()>) {}
+    fn run(&self, _on_finish_launching: Box<dyn FnOnce() -> ()>) {
+        unimplemented!()
+    }
 
     fn dispatcher(&self) -> Arc<dyn super::Dispatcher> {
         self.dispatcher.clone()
diff --git a/zed/src/main.rs b/zed/src/main.rs
index 6d171a5a29..b214924a80 100644
--- a/zed/src/main.rs
+++ b/zed/src/main.rs
@@ -35,7 +35,7 @@ fn main() {
             _ => ctx.dispatch_global_action(command, ()),
         }
     })
-    .on_finish_launching(move |ctx| {
+    .run(move |ctx| {
         workspace::init(ctx);
         editor::init(ctx);
         file_finder::init(ctx);
@@ -54,8 +54,7 @@ fn main() {
                 },
             );
         }
-    })
-    .run();
+    });
 }
 
 fn init_logger() {