I was playn in one of those (WM) realistic CS servers when i found that once i tried to chat, it froze in the chat mode while the game was still running fine in the background. When i clicked, i got out of the chat and then played normally again... I couldnt chat at all OR press escape to the menu for "exit, vote map, vote kick and change team" Anyone experienced this bug before? How to resolve?

Yes, and it's pretty common. I've been around this bug since 1.3 came out. There's no way to resolve it except ALT + CRL + DEL your way out, then restart the game.

you can in most cases also just alt + f4