Hi Marc, that's a helpful illustration!

So I think I understand that left/right will rotate the object in 90 degree steps using a revolve axis that is vertical relative to the current view, and up/down will rotate the object in 90 degree steps using a revolve axis horizontal in the current view.

In the 2D Top/Front/Right views the revolve axis should be in a world x/y/z axis direction, right?

What do you want to happen in a 3D view, should it select a world axis direction that is closest to the current view's up/down or left/right directions?

Or should it rotate around the 3D view's actual local left/right or up/down axis directions which will kind of tilt objects without keeping them aligned to other objects... ?

- Michael