This has happened several times before that for no apparent or related reason while using different software all the fences and and attached icons disappear for no reason... Clicking to get it back does not work. Only fix is to reboot the computer when this happens.
I am running version 18.104.22.168
Additional tweeks, have all selected
Roll up Fences and Quick hide are "NOT" enabled.
I do run multilple Monitors (5)
For what ever reason, this is totally random and happens about once every 2 or 3 weeks without warning.
This is the paid version of Fences