Hi there 
I’m a bit frustrated about how the constrained region drag works and decided to ask if I’m just simply doing something wrong.
When recording instruments in a song I often need to move small mono regions to other tracks. This needs to be done so that the region stays exactly at the time location, so it won’t get out of sync with the other instruments.
I’ve changed the modifier key in: Preferences / Editor / Modifiers: When beginning a drag Constrain drag using: windows - key.
Now when I drag a region holding down the windows key the regions stays fixed in the timeline. But not always. It seems that constrain only works if the first movement you make with the mouse is straight up or down. If the mouse wiggles even a bit constrain will not work and the region will move to a wrong point in time. It gets worse when you zoom out to see the whole of the song (5 - 10 minutes of the session), then it feels like even smaller movements somewhere else than straight up or down will make constrain fail. Mouse is not a perfect tool, so it often wiggles a bit when you touch it.
Music must be perfectly syncronized so I often need many tries when moving regions between tracks. Usually I make a move and notice that the drag was not perfectly constrained, undo, try again, undo try again.
Is constrain meant to prevent the movement in time when dragging or am I just doing something wrong ?