Strange, that should work. What bone do you have selected? That will be the bone you redraw. If you have no bone selected it will use the root. If redrawing a bone that a constraint is controlling, it can make for some surprising behavior, eg normally the new bone will point at the mouse, but the constraint can make it point a different direction.
If you have a project that shows this problem every time, we'd love to see the .spine file with instructions on how to see it for ourselves.
