I can reliably reproduce this by just launching gnome-calendar on mantic. This looks to be the same issue as the upstream https://gitlab.gnome.org/GNOME/gnome-calendar/-/issues/1106 which has an associated fix in https://gitlab.gnome.org/GNOME/gnome- calendar/-/merge_requests/366
** Bug watch added: gitlab.gnome.org/GNOME/gnome-calendar/-/issues #1106 https://gitlab.gnome.org/GNOME/gnome-calendar/-/issues/1106 -- You received this bug notification because you are a member of Desktop Packages, which is subscribed to gnome-calendar in Ubuntu. https://bugs.launchpad.net/bugs/2041478 Title: /usr/bin/gnome- calendar:6:g_assertion_message:g_assertion_message_expr:recalculate_layout_blocks:gcal_month_view_row_add_event:gcal_month_view_add_event Status in gnome-calendar package in Ubuntu: New Bug description: The Ubuntu Error Tracker has been receiving reports about a problem regarding gnome-calendar. This problem was most recently seen with package version 45.0-1, the problem page at https://errors.ubuntu.com/problem/556afecb4d0b594b8bfdac2aa521cb12fa243a76 contains more details, including versions of packages affected, stacktrace or traceback, and individual crash reports. If you do not have access to the Ubuntu Error Tracker and are a software developer, you can request it at http://forms.canonical.com/reports/. To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/gnome-calendar/+bug/2041478/+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