Window help

[Watabou]

Recently when I am doing several things at once, my Firefox/Safari windows sometimes turn weird. By weird, I mean that I can't minimize them as you can see in the screen shot. When I click on the place where the yellow is supposed to be at, it doesn't minimize. The only solution is to restart the damn program. Is there any explanation to this behavior?

 

[redAPPLE]

that looked like a firefox window and not a safari window. are you sure it happens with the safari window too?

 

[Watabou]

that looked like a firefox window and not a safari window. are you sure it happens with the safari window too?

Yep. I have noticed it before. And while I can still minimize my Firefox window my pressing Command+M, the same cannot be said when Safari window becomes like that.