Handle screen changes for non-top-level windows

The platform may emit screen changes for child windows before top-level
windows, so we need to update the top level screen as soon as possible.

Change-Id: I090c620725c9c3171f5b038708d78ddfeec8512d
Reviewed-by: Lars Knoll <lars.knoll@qt.io>
Reviewed-by: Tor Arne Vestbø <tor.arne.vestbo@qt.io>

1 files changed, 3 insertions, 3 deletions

diff --git a/src/gui/kernel/qguiapplication.cpp b/src/gui/kernel/qguiapplication.cpp
index 91348265cd..712699ddc9 100644
--- a/src/gui/kernel/qguiapplication.cpp
+++ b/src/gui/kernel/qguiapplication.cpp
@@ -2338,11 +2338,11 @@ void QGuiApplicationPrivate::processWindowScreenChangedEvent(QWindowSystemInterf
     if (QWindow *window  = wse->window.data()) {
         if (window->screen() == wse->screen.data())
             return;
-        if (window->isTopLevel()) {
+        if (QWindow *topLevelWindow = window->d_func()->topLevelWindow(QWindow::ExcludeTransients)) {
             if (QScreen *screen = wse->screen.data())
-                window->d_func()->setTopLevelScreen(screen, false /* recreate */);
+                topLevelWindow->d_func()->setTopLevelScreen(screen, false /* recreate */);
             else // Fall back to default behavior, and try to find some appropriate screen
-                window->setScreen(0);
+                topLevelWindow->setScreen(0);
         }
         // we may have changed scaling, so trigger resize event if needed
         if (window->handle()) {