Seems to be working very well on my end, too, I think it will make a nice addition to the compiler suite.
One question, though: how did you implement the splitter control? There are a few examples on the web (there's one on smorgasbordet, too), but in these the widths of the treeview/listview are being changed in realtime, which can generate a lot of flicker, especially with the treeview. Yours seems to work the "right way", i.e. it updates the controls on drag release only.
Regards,
Adrian