There seems to be a bug in the implementation of lock track height, where that property sometimes stops to work and the track has its height changed when zooming even though the toggle to lock track height is on. If I turn it off and then on again, things work again as expected, but then at some point (unclear when or how) it stops working again.
Licecap:
First you see that lock track height is checked, then I Ctrl+mousescroll the TCP, and you see that the track indeed changes height. Then I turn the toggle off and Ctr+scroll again and you see that the behavior is the same as it was with the toggle on. Then I toggle it again, and then you see that the track indeed has its height locked when Ctrl+scrolling.