After a while, the trackpad or mouse requires me to click twice to be able to register a single click

I have two macbook pros, one summer 2009 model and a late summer 2011 model. Both of these macbook pros seem to require me to click twice just to be able to register a single click. It's almost like the app loses focus and I have to click twice. I'm not running jiTouch and this happens with both the trackpad and the magic mouse.

This has been happening for months now and seems to be happening on both 10.6 and 10.7.

Any help would be greatly appreciated!

After some testing, I realized that this only seems to happen after I have opened the application "mumble" (a VOIP app). There's also a discussion about it on the sourceforge forums. Here's a link to the sourceforge discussion about this same issue: http://sourceforge.net/projects/mumble/forums/forum/492607/topic/4886530/index/page/1