I just tried PlaneScape: Torment 1.1 (german) on GemRB 0.2.8 (english) using the provided installers.
Installation went fine, game runs, so I edited the pst.cfg to get a resolution higher than 640x480. I tried with 1280x1024 and the map rendered fine, but the UI was unusable.
If I pressed ESC a lot I got it to flicker a bit, otherwise it was invisible. (Only the "clock" was visible.) The group-icons were visible more often than the rest of the UI when I kept pressing ESC. (I had to press faster to make the rest of the menubar also show up.)
When I switched to the minimap, the UI suddenly showed up, but when I closed it, it was again invisible.
Tooltips, mousecursor and characters showed up fine.
Could it be that this is a z-buffer problem? Does pressing ESC repaint the UI?