Happens on almost all v6.0 EAPs. If I leave my project open over night, I got this in the morning. Also today happened while I was closing my project (already 190M occupied, I though that closing the project will solve it). After I close it (I think I closed it as I received an error, but the interface behave like no project was open), the memory usage remained at 190M of 190M.
I know you need more details on this. How can I do a memory dump / stack trace / whatever ?