diff --git a/Cargo.lock b/Cargo.lock
index a175f4ea2..344c03ff1 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -1717,6 +1717,7 @@ dependencies = [
  "ashpd",
  "async-net",
  "bitfield-struct",
+ "block",
  "bytes",
  "ciborium",
  "clap",
diff --git a/gui/Cargo.toml b/gui/Cargo.toml
index 468b0341f..0d356f267 100644
--- a/gui/Cargo.toml
+++ b/gui/Cargo.toml
@@ -85,6 +85,7 @@ windows-sys = { version = "0.59.0", features = [
 
 [target.'cfg(target_os = "macos")'.dependencies]
 applevisor-sys = "0.1.3"
+block = "0.1.6"
 core-foundation = "0.10.0"
 core-foundation-sys = "0.8.7"
 core-graphics-types = "0.1.3"
diff --git a/gui/src/ui/backend/window.rs b/gui/src/ui/backend/window.rs
index 48d3a7dd2..e1d4870d0 100644
--- a/gui/src/ui/backend/window.rs
+++ b/gui/src/ui/backend/window.rs
@@ -180,6 +180,20 @@ impl WindowAdapter for Window {
             assert!(self.visible.get().is_none());
 
             self.winit.set_visible(true);
+
+            // Render initial frame. Without this the modal on macOS will show a blank window until
+            // show animation is complete.
+            let scale_factor = self.winit.scale_factor() as f32;
+            let size = self.winit.inner_size();
+            let size = PhysicalSize::new(size.width, size.height);
+            let size = LogicalSize::from_physical(size, scale_factor);
+
+            self.slint
+                .dispatch_event(WindowEvent::ScaleFactorChanged { scale_factor });
+            self.slint.dispatch_event(WindowEvent::Resized { size });
+
+            self.renderer.render()?;
+
             self.visible.set(Some(true));
         } else if self.visible.get().is_some_and(|v| v) {
             self.winit.set_visible(false);
diff --git a/gui/src/ui/macos/mod.rs b/gui/src/ui/macos/mod.rs
index a0228ddd8..24e0c4dc7 100644
--- a/gui/src/ui/macos/mod.rs
+++ b/gui/src/ui/macos/mod.rs
@@ -1,24 +1,20 @@
+use self::view::with_window;
 use super::PlatformExt;
 use crate::rt::RuntimeWindow;
-use objc::runtime::Object;
+use block::ConcreteBlock;
 use objc::{msg_send, sel, sel_impl};
-use raw_window_handle::{HasWindowHandle, RawWindowHandle};
 use slint::ComponentHandle;
+use std::ffi::c_long;
+use std::ops::Deref;
 use thiserror::Error;
 
+mod view;
+
 impl<T: ComponentHandle> PlatformExt for T {
     fn set_center(&self) -> Result<(), PlatformError> {
-        // Get NSView.
-        let win = self.window().window_handle();
-        let win = win.window_handle().unwrap();
-        let win = match win.as_ref() {
-            RawWindowHandle::AppKit(v) => v.ns_view.as_ptr().cast::<Object>(),
-            _ => unreachable!(),
-        };
-
-        // Get NSWindow and call center() method.
-        let win: *mut Object = unsafe { msg_send![win, window] };
-        let _: () = unsafe { msg_send![win, center] };
+        with_window::<()>(&self.window().window_handle(), |win| unsafe {
+            msg_send![win, center]
+        });
 
         Ok(())
     }
@@ -27,7 +23,17 @@ impl<T: ComponentHandle> PlatformExt for T {
     where
         P: RuntimeWindow + ?Sized,
     {
-        todo!()
+        // Setup completionHandler.
+        let cb = ConcreteBlock::new(move |_: c_long| {}).copy();
+
+        // Show the sheet.
+        let win = self.window().window_handle();
+        let win = with_window(&win, |w| w);
+        let _: () = with_window(parent, |w| unsafe {
+            msg_send![w, beginSheet:win completionHandler:cb.deref()]
+        });
+
+        Ok(())
     }
 }
 
diff --git a/gui/src/ui/macos/view.rs b/gui/src/ui/macos/view.rs
new file mode 100644
index 000000000..cd0e95172
--- /dev/null
+++ b/gui/src/ui/macos/view.rs
@@ -0,0 +1,15 @@
+use objc::runtime::Object;
+use objc::{msg_send, sel, sel_impl};
+use raw_window_handle::{HasWindowHandle, RawWindowHandle};
+
+pub fn with_window<T>(win: impl HasWindowHandle, f: impl FnOnce(*mut Object) -> T) -> T {
+    // Get NSView.
+    let win = win.window_handle().unwrap();
+    let win = match win.as_ref() {
+        RawWindowHandle::AppKit(v) => v.ns_view.as_ptr().cast::<Object>(),
+        _ => unreachable!(),
+    };
+
+    // Get NSWindow.
+    f(unsafe { msg_send![win, window] })
+}