I am finding that at times, IntelliJ 4.5 gets stuck during compilation. It is usually when the dialog says "checking dependencies". If you click the red "stop" button, the build window closes, but you can't restart the compilation without shutting Idea. And when you shut Idea, it gives a warning something about "are you sure you want to close while compiling" (not an exact quote.)
Then when it restarts and you try to compile, it alerts you that the last compile was interrupted and it needs to rebuild the whole project. :(
Are you guys on this one?