I've noticed that when roundcubemail starts checking for new messages - the whole screen is kinda frozen and you can't do much unless and until the check new messages function is over.
Is there anyway to make sure that the screen isn't frozen whilst checking for new messages. SO that you can continue your work whilst the messages download in the background..
what version are you using? i think in 0.2stable the UI is no longer locked during new message check.