You were on the right track. I finally got around to fixing the tooltip-not-hiding-on-mouseout issue, and discovered that there was rather a lot of code being executed repeatedly to refresh the tooltip while it's visible... which, if you use something like DrDamage, ends up being even more code repeatedly run. Removing the refresh code seems to have no effect on functionality, and dramatically reduces the memory gain and FPS lag while tooltips are open. I'll just commit this change on the SVN, along with the self-cast option I'd posted about some time ago.
Edit: Commited. Working for me; let me know if it breaks something for you.
How does the SVN work?Would you show me a link?Sorry for my situpid quetion.>_<