I ran into a major visual ghosting/glitching issue involving TCP/arrange area. (licecap below)
The bug can be reproduced the following way:
1. Create 50 empty tracks.
2. Toggle "Lock Track Height" on for track #50.
3. Marque zoom starting from track #50 going up.
What you will get is the following:
The bug is probably related to the one I reported some time ago
here.