IDEA Says "Compilation Completed Successfully" but it doesn't compile

Every now and then (about 3 time a week), whenever I try to compile my project, IDEA says it compiled it, but, in fact, nothing happened.

there's no compilation progress bar, and while debugging, the modified code isn't accessed. (new variables can't be evaluated etc.)

the only thing possible at this situation is to close and reopen the IDEA, and then it fixes it.

I'm using IntelliJ 10.5.2, JDK 1.6.0, on Linux CentOs.

Thanks alot !

Nati.