Unity web player full screen problem with keys on self-made web-browser

Hello, I've made my own web browser for playing 1 game called UberStrike, and everything works perfect until I go full-screen mode, then TAB key isn't working, nor does the ENTER(chat) key, but when I go to game options to assign the buttons(while in full screen) they work, but not in the game... So how can I fix my browser? Do I have to add some support in the code for unity web player?
I also tried changing the browser's engine on Geckofox and added WebKit.NET and nothing of that helped. Note: my browser is written in C#, and I also wrote another version of it in C++ and same problems occurred.