Mozilla annoyance

Occasionally when using Mozilla (regular Mozilla, hasn’t happened in Firefox) something strange happens: a black box appears around any link I click, the link opens up in a new tab even when I’ve tried to open it in the same tab, and my keyboard stops working. Closing and reopening Mozilla doesn’t fix it, I have to switch to a different browser or reboot. WTF is going on?

Does everything work OK in other applications? It sounds to me like it could be a sticking key on your keyboard - maybe the Control or Alt key? (I’m not sure what the command keys do in Firefox)

My keyboard at work had a sticky Ctrl key, which caused all kinds of weird behaviour.

No, that’s the only program I have problems with.