Looks like there's an upstream bug against Claws Mail, too: https://www.thewildbeast.co.uk/claws-mail/bugzilla/show_bug.cgi?id=4203
** Bug watch added: Claws Mail bugzilla #4203 http://www.thewildbeast.co.uk/claws-mail/bugzilla/show_bug.cgi?id=4203 -- You received this bug notification because you are a member of Desktop Packages, which is subscribed to gtk+2.0 in Ubuntu. https://bugs.launchpad.net/bugs/1808710 Title: !xcb_xlib_threads_sequence_lost error with GTK2 applications Status in gtk+2.0 package in Ubuntu: Confirmed Bug description: GTK2 applications randomly crash or freeze with same error. See attached files. To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/gtk+2.0/+bug/1808710/+subscriptions -- Mailing list: https://launchpad.net/~desktop-packages Post to : desktop-packages@lists.launchpad.net Unsubscribe : https://launchpad.net/~desktop-packages More help : https://help.launchpad.net/ListHelp
