Windows QPA: Find window before invoking native filters

When handling WM_NCCALCSIZE in a global filter, the associated platform
window needs to be assigned to platformWindowPtr so that its frame
margins can be updated on return.
See also 3035400f36731c400adb9204b94e9afe346a71b7, which introduced the
platformWindowPtr out parameter for this purpose.

[ChangeLog][Platform Specific Changes][Windows] Fixed frameMargins for
WM_NCCALCSIZE when handled inside with QAbstractNativeEventFilter.

Change-Id: I7827b81d30a5c80dad591206a88712169dea0108
Reviewed-by: Friedemann Kleint <Friedemann.Kleint@qt.io>

1 files changed, 3 insertions, 2 deletions

diff --git a/src/plugins/platforms/windows/qwindowscontext.cpp b/src/plugins/platforms/windows/qwindowscontext.cpp
index ff4ab1accb..eb62bd2e1f 100644
--- a/src/plugins/platforms/windows/qwindowscontext.cpp
+++ b/src/plugins/platforms/windows/qwindowscontext.cpp
@@ -855,6 +855,9 @@ bool QWindowsContext::windowsProc(HWND hwnd, UINT message,
         GetCursorPos(&msg.pt);
     }
 
+    QWindowsWindow *platformWindow = findPlatformWindow(hwnd);
+    *platformWindowPtr = platformWindow;
+
     // Run the native event filters.
     long filterResult = 0;
     QAbstractEventDispatcher* dispatcher = QAbstractEventDispatcher::instance();
@@ -863,8 +866,6 @@ bool QWindowsContext::windowsProc(HWND hwnd, UINT message,
         return true;
     }
 
-    QWindowsWindow *platformWindow = findPlatformWindow(hwnd);
-    *platformWindowPtr = platformWindow;
     if (platformWindow) {
         filterResult = 0;
         if (QWindowSystemInterface::handleNativeEvent(platformWindow->window(), d->m_eventType, &msg, &filterResult)) {