If I added a UV Sphere and then a cube, could I return to the operator panel for the UV sphere and make changes or is the opportunity lost once I move on?
I just started using Blender for the third time. Keep losing focus. If I recall correctly you are not able to get back to the operator panel for the creation of a sphere to add more rings or segments. However, there are manual ways to overcome this. I don't remember what those are though.