winit-win32: fix request_redraw can be ignored while the system popup menu is shown

winit-win32/src/event_loop.rs

@@ -49,17 +49,17 @@ use windows_sys::Win32::UI::WindowsAndMessaging::{
     SC_MINIMIZE, SC_RESTORE, SIZE_MAXIMIZED, SPI_GETWHEELSCROLLCHARS, SPI_GETWHEELSCROLLLINES,
     SWP_NOACTIVATE, SWP_NOMOVE, SWP_NOSIZE, SWP_NOZORDER, SetCursor, SetWindowPos,
     SystemParametersInfoW, TranslateMessage, WHEEL_DELTA, WINDOWPOS, WM_CAPTURECHANGED, WM_CLOSE,
-    WM_CREATE, WM_DESTROY, WM_DPICHANGED, WM_ENTERSIZEMOVE, WM_EXITSIZEMOVE, WM_GETMINMAXINFO,
-    WM_IME_COMPOSITION, WM_IME_ENDCOMPOSITION, WM_IME_SETCONTEXT, WM_IME_STARTCOMPOSITION,
-    WM_INPUT, WM_INPUTLANGCHANGE, WM_KEYDOWN, WM_KEYUP, WM_KILLFOCUS, WM_LBUTTONDOWN, WM_LBUTTONUP,
-    WM_MBUTTONDOWN, WM_MBUTTONUP, WM_MENUCHAR, WM_MOUSEHWHEEL, WM_MOUSEMOVE, WM_MOUSEWHEEL,
-    WM_NCACTIVATE, WM_NCCALCSIZE, WM_NCCREATE, WM_NCDESTROY, WM_NCLBUTTONDOWN, WM_PAINT,
-    WM_POINTERDOWN, WM_POINTERUP, WM_POINTERUPDATE, WM_RBUTTONDOWN, WM_RBUTTONUP, WM_SETCURSOR,
-    WM_SETFOCUS, WM_SETTINGCHANGE, WM_SIZE, WM_SIZING, WM_SYSCOMMAND, WM_SYSKEYDOWN, WM_SYSKEYUP,
-    WM_TOUCH, WM_WINDOWPOSCHANGED, WM_WINDOWPOSCHANGING, WM_XBUTTONDOWN, WM_XBUTTONUP, WMSZ_BOTTOM,
-    WMSZ_BOTTOMLEFT, WMSZ_BOTTOMRIGHT, WMSZ_LEFT, WMSZ_RIGHT, WMSZ_TOP, WMSZ_TOPLEFT,
-    WMSZ_TOPRIGHT, WNDCLASSEXW, WS_EX_LAYERED, WS_EX_NOACTIVATE, WS_EX_TOOLWINDOW,
-    WS_EX_TRANSPARENT, WS_OVERLAPPED, WS_POPUP, WS_VISIBLE,
+    WM_CREATE, WM_DESTROY, WM_DPICHANGED, WM_ENTERMENULOOP, WM_ENTERSIZEMOVE, WM_EXITMENULOOP,
+    WM_EXITSIZEMOVE, WM_GETMINMAXINFO, WM_IME_COMPOSITION, WM_IME_ENDCOMPOSITION,
+    WM_IME_SETCONTEXT, WM_IME_STARTCOMPOSITION, WM_INPUT, WM_INPUTLANGCHANGE, WM_KEYDOWN, WM_KEYUP,
+    WM_KILLFOCUS, WM_LBUTTONDOWN, WM_LBUTTONUP, WM_MBUTTONDOWN, WM_MBUTTONUP, WM_MENUCHAR,
+    WM_MOUSEHWHEEL, WM_MOUSEMOVE, WM_MOUSEWHEEL, WM_NCACTIVATE, WM_NCCALCSIZE, WM_NCCREATE,
+    WM_NCDESTROY, WM_NCLBUTTONDOWN, WM_PAINT, WM_POINTERDOWN, WM_POINTERUP, WM_POINTERUPDATE,
+    WM_RBUTTONDOWN, WM_RBUTTONUP, WM_SETCURSOR, WM_SETFOCUS, WM_SETTINGCHANGE, WM_SIZE, WM_SIZING,
+    WM_SYSCOMMAND, WM_SYSKEYDOWN, WM_SYSKEYUP, WM_TOUCH, WM_WINDOWPOSCHANGED, WM_WINDOWPOSCHANGING,
+    WM_XBUTTONDOWN, WM_XBUTTONUP, WMSZ_BOTTOM, WMSZ_BOTTOMLEFT, WMSZ_BOTTOMRIGHT, WMSZ_LEFT,
+    WMSZ_RIGHT, WMSZ_TOP, WMSZ_TOPLEFT, WMSZ_TOPRIGHT, WNDCLASSEXW, WS_EX_LAYERED,
+    WS_EX_NOACTIVATE, WS_EX_TOOLWINDOW, WS_EX_TRANSPARENT, WS_OVERLAPPED, WS_POPUP, WS_VISIBLE,
 };
 use winit_core::application::ApplicationHandler;
 use winit_core::cursor::{CustomCursor, CustomCursorSource};
@@ -1177,14 +1177,33 @@ unsafe fn public_window_callback_inner(
             result = ProcResult::Value(0);
         },
 
+        WM_ENTERMENULOOP => {
+            userdata.window_state_lock().menu_loop_depth += 1;
+            result = ProcResult::Value(0);
+        },
+
+        WM_EXITMENULOOP => {
+            // Redraw requests made during the menu loop can be dropped by the system (#4608).
+            // Call pending redraw once the loop has exited.
+            let should_redraw = {
+                let mut state = userdata.window_state_lock();
+                state.menu_loop_depth = state.menu_loop_depth.saturating_sub(1);
+                state.menu_loop_depth == 0 && mem::take(&mut state.redraw_requested)
+            };
+            if should_redraw {
+                unsafe { RedrawWindow(window, ptr::null(), ptr::null_mut(), RDW_INTERNALPAINT) };
+            }
+            result = ProcResult::Value(0);
+        },
+
         WM_PAINT => {
-            userdata.window_state_lock().redraw_requested =
-                userdata.event_loop_runner.should_buffer();
+            let should_buffer = userdata.event_loop_runner.should_buffer();
+            userdata.window_state_lock().redraw_requested = should_buffer;
 
             // We'll buffer only in response to `UpdateWindow`, if win32 decides to redraw the
             // window outside the normal flow of the event loop. This way mark event as handled
             // and request a normal redraw with `RedrawWindow`.
-            if !userdata.event_loop_runner.should_buffer() {
+            if !should_buffer {
                 userdata.send_window_event(window, WindowEvent::RedrawRequested);
             }
 
@@ -1193,7 +1212,11 @@ unsafe fn public_window_callback_inner(
             // user asked for redraw during `RedrawRequested` event handling and request it again
             // after marking `WM_PAINT` as handled.
             result = ProcResult::Value(unsafe { DefWindowProcW(window, msg, wparam, lparam) });
-            if std::mem::take(&mut userdata.window_state_lock().redraw_requested) {
+            let should_redraw = {
+                let mut state = userdata.window_state_lock();
+                state.menu_loop_depth == 0 && mem::take(&mut state.redraw_requested)
+            };
+            if should_redraw {
                 unsafe { RedrawWindow(window, ptr::null(), ptr::null_mut(), RDW_INTERNALPAINT) };
             }
         },

winit-win32/src/window_state.rs

@@ -60,6 +60,7 @@ pub(crate) struct WindowState {
 
     // Flag whether redraw was requested.
     pub redraw_requested: bool,
+    pub menu_loop_depth: u32,
 
     pub dragging: bool,
 
@@ -191,6 +192,7 @@ impl WindowState {
             is_active: false,
             is_focused: false,
             redraw_requested: false,
+            menu_loop_depth: 0,
 
             dragging: false,
 

winit/src/changelog/unreleased.md

@@ -67,4 +67,5 @@ changelog entry.
 - On macOS, fix borderless game presentation options not sticking after switching spaces.
 - On macOS, fix IME being locked on (regardless of requests to disable) after being enabled once.
 - On macOS, fix a panic and incorrect cursor position in Ime::Preedit when the preedit string contains special characters (ie. emojis) caused by incorrect UTF-16 to UTF-8 offset conversion.
+- On Windows, fix `request_redraw` calls are ignored while the system popup menu is shown.
 - On Wayland, fix a protocol error when setting a custom cursor on compositors with `wl_surface` version below 3.