Event Filter & No Focus problem

Um hi. Here is a problem. We have one terrible project where we can't use any windows manager. Event filter needed for showing small panel in our program with any other forms opened. That works fine. But in that panel user have to press some F buttons. And here comes Mrs Huge Problem and her partner Mr. Not Understand. When program tested on PC with windows manager everything works ok. But on um... PC without wind. man. it just doesn't work when this panel hasn't focus on it. We tried sending pointer of that event filter class into panel program and send some slots which will tell it that panel closing or shown then even filter can properly process it (we kinda rebuild event filter a little bit) but still no luck. Same problem.

I hope I described problem more or less clear and someone can help :-)