Funny Firefox bug

Happens only in Windows, at work, so I'm not really bothered about it:

When I try to open a link in a new tab by clicking the mouse scroll wheel, nothing happens till I move the mouse, even if only by a fraction of a millimeter. If I don't do this, Firefox simply sits there, looking at me dumbly, and not doing anything about my request, till I say Alright, you win and tap the mouse ever so slightly.