Clipman panel plugin incorrectly remembering mouse selections

[Matt Connell]

On Thu, 2023-05-25 at 16:16 +0200, Guido Falsi wrote:
> AFAIK the selection buffer is something X11 does, cannot be disabled by 
> clients (maybe there is an Xorg/Xserver configuration or option, never 
> checked). I guess clipman is only displaying what gets put in there by Xorg.

Interesting.  I didn't even know this was an X11... I guess its a
feature, based on some reading, and a very old one at that.  It sounds
like absolute madness to me; why would a user assume any highlighted
text would be copied?

Regardless, I threw some spaghetti at the wall and something stuck:
*enabling* "sync mouse selection" achieved the desired result.  No more
screen-sized wall of text appearing in the clipman menu any time I
highlight a bunch of text to delete.