Sometimes, when I use synergy between my machines when one is using full-screen VirtualBox guest I get stuck with some weird key modifiers turned on. If they exist on my keyboard (like Shift_L) I can just tap it and their status is reset and I can continue typing in small letters. But some of them are not mapped to my keyboard at all (like ISO_Level3_Shift), so I have no means of turning them off at all!
How to reset them? Right now, all I can do is to reboot the computer, but it's rather embarrassing solution.
All I want is some program that can artificially "tap" all possible keyboard modifiers, so their status would be reset. Can it be done?
I use Mint 14 (a clone of Ubuntu 12.10 Quantal).