Don't know if this is a bug or not, but one of my projects has a hinge rotator in it and it doesn't turn. I've changed activation groups and moved the part, but still nothing. It is xml modded to be smaller, but even using a regular size one won't work.
Every other plane I load they work fine, it's just on one of them.
The piece is attached to something else even though it looks as if it's on the hinge rotator, this is normal. Just nudge the hinge rotator out and then put the piece on there then nudge the pieces back to where you want them.
Maybe part you are trying to move got attached to something else.