[SSJKarma]

first things first...

is the keys not responding ?
if yes, try the following...
-- click on the game to give it focus, even if the bar is already blue.
-- if in chat box, you cannot talk unless you click in the chat box itself.

if the first solution works and the bug reappear and you have to reclick on the game again. then there is something (program) that is running in the Background who actually give the focus to itself, thus making the game lose focus and your key aren't responding if the game don't have the focus.

have a nice day/night and i hope i have been of some help !