Group Window has vanished never to return!!
 

Cant for the life of my get my group window to return,
have deleted full ui and reinstalled it to no avail.
been using this ui for years and this has never happened, its missing on all my toons for some reason.

On my system it's Alt-G to toggle it off and on. And if you aren't in a group you can toggle it on but it's a blank background with no frame so unless it's got a darkened background or you use F10 you may not be able to see it.