I discovered a weird bug with take lanes last night:
I couldn't move clips in one of the take lanes. the other two lanes were fine, but once i moved a clip into Lane#1, it was "stuck" there.
Drove me crazy until I noticed that Lane#1 was in EventFilter="Clip Gain", not "Clips". Note - the colour scheme on Lane#1 was not showing the "clip gain" filter scheme, it was totally looking like normal "clips" mode.
So if you find yourself unable to move clips between lanes, perhaps you are experiencing the same issue. Double-check the lane-specific event filter settings.