36fadb4c13
QMainWindowLayout re-uses tab bars. A QSet and a QList member are kept, to track used and unused tab bars. Corner cases upon application close down leave dangling pointers in those containers. => Add a destructor to QMainWindowTabBar => remove the tab bar from used and unused tab bar containers, if not directly parented to the main window. => No longer reparent unused tab bars of a QDockWidgetGroupWindow to the main window. Let them be destroyed as a group window child, and its destructor remove it from the used/unused tab bar container. Pick-to: 6.5 Change-Id: If2388cf878553dc89583dbc8585748fad65bbab2 Reviewed-by: Volker Hilsheimer <volker.hilsheimer@qt.io> (cherry picked from commit b6b489db6968fbc3b4aab3755d0166ee09712ff0) Reviewed-by: Qt Cherry-pick Bot <cherrypick_bot@qt-project.org>