Created attachment 106430 [details] Source code of the progress-dialog example The problem first arose while running Rosegarden and is related to using the QProgressDialog widget. The attached progress-dialog tiny program reproduced it. From plasma desktop: - Start progress-dialog application: A small window with a start button appears. - Click the start button: A message box "Wait four seconds..." with an OK button is shown. - Wait about four seconds: A Qprogress dialog "Opening file..." with a Cancel button pops up (sometimes hidden under the first window) and the desktop freezes. The digital and analog clocks are no more counting seconds and menus are unusable. Neither the OK nor the Cancel buttons are working. - Moving a window is still possible: A soon as a window has been moved, the desktop is no more frozen. - Clicking on the OK or Cancel button freezes again the desktop. - Clicking repeatedly the Cancel button does it works eventually. There is no such problem when running the same application from some other desktop session (I tried Gnome and IceWM).
Was able to reproduce this bug once. Desktop freezes upon "Opening file..." dialog - dragging fullscreen (Firefox) window unfroze the desktop. Cannot reproduce this bug currently.
Can you please test and confirm if this issue is still occurring or if this bug report can be marked as resolved. I'm setting status to "needsinfo" pending your response, please change back to "resolved" or "reported" when you respond, thanks.
That was three years ago and I don't well remember what the problem was. Some workaround for Rosegarden has been added long ago. I still can reproduce the attachment 106430 [details] problem today on an old system : KDE Frameworks 5.42.0 / Qt 5.9.4. I can't reproduce it on a recent system : KDE Frameworks 5.75.0 / Qt 5.15.1. So there is no more issue and the problem is now fixed. I set the bug status to "resolved". Thanks.