The Y Offset was designed in, but I can't remember why now!
I've removed it in V5 (to be released later today)

I might make "drag without shift" an option, but in testing it was possible to select a part, then whilst attempting to select another part cause a drag (it only takes a pixel difference in any direction). So the old part moved instead of the new part being selected...

Let me see how far I get with the other requests... =)