I wonder is there a way to show multiple World axis icons in the viewport while their respective saved custom CPlanes are being selected simultaneously with the Shift or Ctrl key in the “Named Cplanes” list? That would be helpful to figure out where they are located in the 3d space, especially when deleting unnecessary CPlanes.
Also, there is no “Undo” option to restore a deleted CPlane.
And no pop-up window to ask for a confirmation to delete a CPlane or multiple CPlanes. Maybe these will be considered for implementation in Rhino 7?
Another idea. When a CPlane is active, can it be marked in the “Named CPlanes” list (with bold text or a colour) so that the user gets a clear idea which one is active at the moment?
A “Flip CPlane” command would be also nice. At the moment flipping a CPlane is somehow possible with the “Rotate SPlane” and using “X” or “Y” as an axis for the rotation and entering 180 degrees. “Flip Cplane” could use automatic “Y” axis to quickly flip the CPlane, OR bring “Flip along X” and “Flip along Y” option in the command prompt.