Menu Editor for Flat Sets

Using the Menu Editor I can create a custom menu in ProjectWise and when I select Documents everything works fine but not Document Sets.
I am using Command Type: Document Command
Required Mask: 1 (Documents), 2 (Document Sets)

I have tried making the Mask 0 but it makes no difference, I still cannot use my custom menu on Flat Sets.
What am I missing?

ProjectWise 10.00.03.434