I was in the MP Menu, chatting. Got a pm from KoboldButter. Switched to the PM tab to read it. tried to switch back to world chat... and found I was stuck on the Friend Tab. While stuck in the friend tab I was able to click on friend's names and message them (though I could not click on the chat window that the message opened). I attempted to search for KoboldButter's name and reply to his message, but he was unsearchable (though he was online). I didn't try searching for other non-friends, but am thinking it would not have worked for them, either. I could not access any menus or click anywhere on the screen other than the friend tab (which I could not close).