gsd-locate-pointer can grab mouse and never release it
The most damning evidence is:
May 10 03:42:48 redacted /usr/lib/gdm3/gdm-x-session[2117]: (II) Printing all currently active device grabs: May 10 03:42:48 redacted /usr/lib/gdm3/gdm-x-session[2117]: Active grab 0x41a00052 (core) on device 'Virtual core pointer' (2): May 10 03:42:48 redacted /usr/lib/gdm3/gdm-x-session[2117]: client pid 2467 /usr/lib/gnome-settings-daemon/gsd-locate-pointer May 10 03:42:48 redacted /usr/lib/gdm3/gdm-x-session[2117]: at 11278056 (from passive grab) (device frozen, state 6) May 10 03:42:48 redacted /usr/lib/gdm3/gdm-x-session[2117]: core event mask 0x4 May 10 03:42:48 redacted /usr/lib/gdm3/gdm-x-session[2117]: passive grab type 4, detail 0x0, activating key 0 May 10 03:42:48 redacted /usr/lib/gdm3/gdm-x-session[2117]: owner-events false, kb 1 ptr 0, confine 0, cursor 0x0 May 10 03:42:48 redacted /usr/lib/gdm3/gdm-x-session[2117]: (II) End list of active device grabs
When this happens, (obviously) all clicks and mouse events stop going through to any programs, including gnome-shell also annoying is the fact that anything that attempts to grab the mouse is met with:
May 09 23:21:01 redacted gnome-shell[2250]: pushModal: invocation of begin_modal failed which includes all menus, the desktop overview, and the gnome-shell alt-f2 command-entry dialog.