Hi, I just got Rhino WIP to freeze/hang when I tried to duplicate/rightclick-select-copy on a material that was assigned to a layer. I clicked the material icon for the layer and right clicked the material assigned and selected “copy” and Rhino froze. Cycles was running.
Edit: Clicking the “x” to close the material manager terminated it. Then I could copy-paste the material in material editor and assign the new material to the layer.