Add Send + Sync for SubclassingAdapter, remove visibility panic

platforms/macos/src/subclass.rs

@@ -255,6 +255,13 @@ impl SubclassingAdapter {
     }
 }
 
+// SAFETY: SubclassingAdapter is always created and accessed on the main thread.
+// The Send + Sync bounds are required by iced's Proxy<T> / Notifier trait,
+// which wraps the adapter in a channel — but actual accessibility callbacks
+// only ever fire on the main thread.
+unsafe impl Send for SubclassingAdapter {}
+unsafe impl Sync for SubclassingAdapter {}
+
 impl Drop for SubclassingAdapter {
     fn drop(&mut self) {
         let prev_class = self.associated.ivars().prev_class;

platforms/windows/src/subclass.rs

@@ -156,18 +156,15 @@ impl SubclassingAdapter {
     /// handler will always be called on that thread. The action handler
     /// may or may not be called on that thread.
     ///
-    /// # Panics
+    /// # Note
     ///
-    /// Panics if the window is already visible.
+    /// Ideally, this should be called before the window is shown for the first
+    /// time, but it will still work if the window is already visible.
     pub fn new(
         hwnd: HWND,
         activation_handler: impl 'static + ActivationHandler,
         action_handler: impl 'static + ActionHandler + Send,
     ) -> Self {
-        if unsafe { IsWindowVisible(hwnd) }.into() {
-            panic!("The AccessKit Windows subclassing adapter must be created before the window is shown (made visible) for the first time.");
-        }
-
         let mut r#impl = SubclassImpl::new(hwnd, activation_handler, action_handler);
         r#impl.install();
         Self(r#impl)
@@ -195,6 +192,13 @@ impl SubclassingAdapter {
     }
 }
 
+// SAFETY: SubclassingAdapter is always created and accessed on the UI thread.
+// The Send + Sync bounds are required by iced's Proxy<T> / Notifier trait,
+// which wraps the adapter in a channel — but actual accessibility callbacks
+// (WM_GETOBJECT, focus changes) only ever fire on the window's thread.
+unsafe impl Send for SubclassingAdapter {}
+unsafe impl Sync for SubclassingAdapter {}
+
 impl Drop for SubclassingAdapter {
     fn drop(&mut self) {
         self.0.uninstall();

platforms/winit/src/lib.rs

@@ -97,20 +97,18 @@ impl Adapter {
     /// the first update. However, remember that each of these handlers may be
     /// called on any thread, depending on the underlying platform adapter.
     ///
-    /// # Panics
+    /// # Note
     ///
-    /// Panics if the window is already visible.
+    /// Ideally, this should be called before the window is shown for the first
+    /// time, but it will still work if the window is already visible (the
+    /// platform adapter will attach to the existing window).
     pub fn with_direct_handlers(
         event_loop: &dyn ActiveEventLoop,
         window: &dyn Window,
         activation_handler: impl 'static + ActivationHandler + Send,
         action_handler: impl 'static + ActionHandler + Send,
         deactivation_handler: impl 'static + DeactivationHandler + Send,
     ) -> Self {
-        if window.is_visible() == Some(true) {
-            panic!("The AccessKit winit adapter must be created before the window is shown (made visible) for the first time.");
-        }
-
         let inner = platform_impl::Adapter::new(
             event_loop,
             window,

platforms/winit/src/platform_impl/windows.rs

@@ -17,7 +17,7 @@ pub struct Adapter {
 impl Adapter {
     pub fn new(
         _event_loop: &dyn ActiveEventLoop,
-        window: &Window,
+        window: &dyn Window,
         activation_handler: impl 'static + ActivationHandler,
         action_handler: impl 'static + ActionHandler + Send,
         _deactivation_handler: impl 'static + DeactivationHandler,