Right, so, if you’re using Sublime Merge on Linux (Wayland, e.g., Fedora Silverblue like me) and, after an external monitor configuration change it starts hanging your entire system (crashing and taking #GNOME with it, requiring a full restart), the workaround is to delete its session file which stores the (now illegal) last-known location of its window.
i.e., Run:
rm ~/.config/sublime-merge/Local/Session.sublime_session