Select Edge not working in Rhino6 - how to?

To no Avail I cannot select an edge of a box with ctrl+Shift click. this was possible in Rhino5. Any help is greatly appreciated.

Please post a file with that box in it.

Figured it out. Cannot select surface edge in Rendered viewport.

You should be able to select a surface of Extrusion edge in the default Rendered working display mode.
I just tested it here to be sure.

Something is probably odd either with the object or with your Rendered display mode settings.
Have you modified “Rendered”?

Not that I know of. I used custom environment maps on the objects though.

Hi Jack - can you run SystemInfo in Rhino and post the results here?