Apparently it's a bug in libx11, which persisted for a long time but became much more likely with an update in libxcb. Please see the still open merge request/patch at
https://gitlab.freedesktop.org/xorg/lib/libx11/-/merge_requests/34 Further reading: This bug report (as it turned out now, it's probably *not* a bug in gtk though): https://gitlab.gnome.org/GNOME/gtk/-/issues/2767 ** Bug watch added: gitlab.gnome.org/GNOME/gtk/-/issues #2767 https://gitlab.gnome.org/GNOME/gtk/-/issues/2767 -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1782984 Title: PCManFM freezes with Assertion `!xcb_xlib_threads_sequence_lost' failed when clicking on a file or folder in 18.04 To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/pcmanfm/+bug/1782984/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
