In the world of not-necessarily obvious, look at the extra-compact spin buttons from the Property Bar when an ellipse is selected:
Those work like the other spin buttons, but you don't click between the arrows. Instead, you have to click on the area right below a pair of down/up arrows. It's the same - but different!
I don't know if one exists, but a new user might benefit from having some reference document that describes all of the different types of controls used in the CorelDRAW UI.