Hello.
Found this behavior with Firefox 3, Google chrome. if session expired message appear while the modal window is showing, you cannot do anything, everything freezes, I don’t know if this is a bug, or something else.
Here is a sample screen
vbnet
definitely sounds like a bug. Please add a ticket for it on dev.itmill.com.
The ticket for this issue is here: http://dev.itmill.com/ticket/2097