Weird Firefox & Thunderbird Context Menu/Right Click Bug

[NicoHood <archlinux@xxxxxxxxxxx>]

Hey guys,
I dont know where to report this, as it could be related to firefox, 
thunderbird or gnome (or any other desktop related software).

In the last 1-2 Weeks (I dont update that often) I noticed that after 
some time (have not found a reproducible reason) right clicks, or 
context menus in genral in Firefox stop working at all. The menu pops up 
for a few milliseconds and then disappear.

When you restart firefox everything works again. I noticed the same isse 
in thunderbird too, which is also by mozilla. I did not notice it in any 
other application. I am using gnome as Desktop environment.

Do you have the same issue? Any hint if this is a gnome, firefox or 
other issue?

Cheers
Nico