Windows QPA: Fix QGuiApplication::topLevelAt() with screen recorder applications

Special applications like screen recorders can create special, invisible
windows which are detected by the ChildWindowFromPointEx() as used in
QWindowsContext::findPlatformWindowAt(). Fall back to WindowFromPoint()
which skips those in case nothing is found.

Fixes: QTBUG-40815
Change-Id: Idb5253c412fb4522c844edf5eadedc6e0fad3979
Reviewed-by: André de la Rocha <andre.rocha@qt.io>
 
 
 

1 files changed, 6 insertions, 0 deletions

diff --git a/src/plugins/platforms/windows/qwindowscontext.cpp b/src/plugins/platforms/windows/qwindowscontext.cpp
index 55e7e32979..e7ac01e411 100644
--- a/src/plugins/platforms/windows/qwindowscontext.cpp
+++ b/src/plugins/platforms/windows/qwindowscontext.cpp
@@ -749,6 +749,12 @@ QWindowsWindow *QWindowsContext::findPlatformWindowAt(HWND parent,
     QWindowsWindow *result = nullptr;
     const POINT screenPoint = { screenPointIn.x(), screenPointIn.y() };
     while (findPlatformWindowHelper(screenPoint, cwex_flags, this, &parent, &result)) {}
+    // QTBUG-40815: ChildWindowFromPointEx() can hit on special windows from
+    // screen recorder applications like ScreenToGif. Fall back to WindowFromPoint().
+    if (result == nullptr) {
+        if (const HWND window = WindowFromPoint(screenPoint))
+            result = findPlatformWindow(window);
+    }
     return result;
 }