Just reporting this in case it’s not already filed as a bug:
If you rotate a shape in the GFUI, you can constrain the rotation to increments of 45 degrees by depressing and holding the Shift key down while rotating. However, if you start rotating and THEN click shift, the rotation will be in 45 degree increments offset from whatever rotation you had before the shift key was pressed.
Before some developer calls this a feature, I will point out that none of the major illustration/drawing/CAD programs work this way.