Hmm interesting, will try to reproduce it. I know there are some problems with the material editor, that’s on the list of bugs to fix.
EDIT: I tried to reproduce it. I saw the increase of memory, will look into it, but couldn’t get it to crash. Can you post a screen? Also, a couple versions back the engine crashed when I switched from the material editor back to the viewport, if I had the mat editor still opened. That went away as magically as it appeared, so it’s probably related.