Every now and then when I click or add a new window,
- the entire screen freezes,
- it turns purple, and
- then the windows reappear again.
I recorded it here
Started when I was playing Minecraft and the pc froze, so I force-shutdown my computer.
note: Its not touchscreen.
note: I tried sudo apt reinstall ubuntu-desktop and re-logged-in. Didn't work.
Apparently xcb crashes:
Apr 16 19:31:03 gnome-shell[14975]: [xcb] Unknown sequence number while processing queue
Apr 16 19:31:03 gnome-shell[14975]: [xcb] Most likely this is a multi-threaded client and XInitThreads has not been called
Apr 16 19:31:03 gnome-shell[14975]: [xcb] Aborting, sorry about that.
Apr 16 19:31:03 gnome-shell[14975]: gnome-shell: ../../src/xcb_io.c:260: poll_for_event: Assertion `!xcb_xlib_threads_sequence_lost' failed.
Apr 16 19:31:03 gnome-shell[14975]: GNOME Shell crashed with signal 6
It usually happens when I use applications that have custom GUIs (e.g. Gedit, Settings, Firefox, Emacs, System Monitor, Haguichi), and when I open/close windows.