I found that you must enter an angle (numerical) in the Size and Position
Window. You can open the SPW by right clicking on the text window, select
View, then Size and Position Window. If you try to rotate using the green
handlebar, it defaults to a 15 degree snap.
When rotating the shape move it, move the cursor further from the shape and
you will notice the snap angle decreases. So the closer you are to the shape
the bigger the increment.