Hello, I got now a clarification in [KDE-396096]. There was a workaround attempted in [KDE-395346], but that led to another crash [KDE-395732] and got therefore reverted.
Upstream it is handled in [QTBUG-68997], that got a fix in Qt 5.12. But except to wait for Qt 5.12 there is a workaround to just switch to another theme. In my case switching to Breeze window decorations works. Can you confirm this? Kind regards, Bernhard [KDE-396096] https://bugs.kde.org/show_bug.cgi?id=396096 [KDE-395346] https://bugs.kde.org/show_bug.cgi?id=395346 [KDE-395732] https://bugs.kde.org/show_bug.cgi?id=395732 [QTBUG-68997] https://bugreports.qt.io/browse/QTBUG-68997