Overlays are positioned so that they are centered over the content item within the window. If the window has a null-size when this is computed, then the overlay ends up being misplaced, and overlay-provided services, such as modality or closing popups, stops working for parts of the UI. Fix this by resizing the offscreen window before resizing the content item. Add a second test case that verifies that the overlay geometry is as it should be, both after the initial show, and after resizing the widget. The existing resizeOverlay test doesn't use a proper QQuickOverlay, so it doesn't cover all the relevant code. Adjustment for 6.5: the test case fails for SizeViewToRootObject in 6.5 as the overlay does not follow the size of the content item in that version. Mark that as an expected failure. Fixes: QTBUG-125135 Task-number: QTBUG-115536 Change-Id: I682d87f07051d213d3bd58c1c2533c84b50a3139 Reviewed-by: Mitch Curtis <mitch.curtis@qt.io> (cherry picked from commit f71ef0d8b8d25b80833228fe4e4bfa716bceb398) Reviewed-by: Qt Cherry-pick Bot <cherrypick_bot@qt-project.org> (cherry picked from commit 9c0aa4cbb7fb50804ce4d1fd1841c49b2866a7af)