The test function shows and activates a custom widget with a hidden QLineEdit inside. It used QApplicationPrivate::setActiveWindow() to force-set the active window. It then sent a mouse double click to the custom window, which would subsequently show the line edit, set focus on it and process events. The use of QApplicationPrivate::setActiveWindow() and setting focus to the line edit could cause a race codition, function call overrides the line edit activation and its widget parent gets focus instead. Remove calls to QApplicationPrivate::setActiveWindow(). Wait for the line edit to be focused, before returning from the mouseDoubleClickEvent() override. Unblacklist the test function. As a drive-by: Remove unnecessary casts, optimize setting of window titles and object names. Fixes: QTBUG-64446 Fixes: QTBUG-84259 Pick-to: 6.10 6.8 6.5 Change-Id: I92953942db9c47ec08b7867928853753fd764798 Reviewed-by: Richard Moe Gustavsen <richard.gustavsen@qt.io> (cherry picked from commit 39dc9b1d6634f6fbd6be3f80f423afee36e7f79a) Reviewed-by: Qt Cherry-pick Bot <cherrypick_bot@qt-project.org>