Memory leaking?

Hmm, since either 963 or 977 (still evident in 992), if I leave Idea running for long periods of time it chews up all the memory allocated to it and eventually pops up an out of memory dialog. This takes some time, but I dont know how long since I usually leave Idea running when I pop off to bed - and its when I return that the dialog is there waiting for me.

I've tried increasing Idea's mem allocation - but it will literally suck everything that I give it.