Panel 'Launch New Instance' hangs desktop for gvim

When I have gvim instances running and right click its icon grouped together on my xfce4 panel and by accident select 'Launch New Instance' this hangs my xfce4 session. The keyboard cursor is first still blinking but disappears after a first mouse click. From hereafter there is no visible response to mouse or keyboard actions beside mouse pointer movement. Alt+F4 or Alt-tab or the keys to switch desktops all do nothing.

This launcher bug has been there a while - a few years. I never found anything reported or a solution, so it could be a local config issue.

A crash-landing solution is Ctrl+Alt+F2, and after login:

pidof xfce4-session | xargs -r kill -9 && startxfce4

BTW, I always run startxfce4 from the terminal console user login.

When I haven't killed my session yet, I see an App launcher in my ps aux, which I suspect, but even a kill -9 just renders it defunct (ps aux), without returning my desktop on Ctrl+Alt+F1. Maybe the underlying cause is that gvim always spawns? The App launcher might get zombified as a process?

There might be a better session saving --reset, but it is not any of these:

xfwm4 --replace --display=:0.0
xfce4-app-finder --quit --display=:0.0
xfce4-app-finder --replace --display=:0.0
xfce4-panel --restart --display=:0.0
xfce4-panel --quit --display=:0.0

Running any of these (except one of the --quit commands) just seem to hang. There doesn't seem any suspicious logs in my journalctl -xb regarding this, (syslog messages since boot).

Distribution is a rolling (reasonably up-to-date) arch-Linux.