So without there being a Reset Rotation Angle to Zero function with this new release, you are stuck with its creation angle being fixed.
This may be OK for QuickShapes but not for Editable Shapes.

The only workaround I have found is to copy the Editable Shape into an earlier Xara Desktop application, make your rotation to set up the required Zero angle and copy & paste back into v16.3!

A replay of the Squishy/Squashy Saga, the Separate images for group members Imbroglio and the SmartShape Frisson.

Acorn