Not sure if this is exclusive to the WIP.
If I toggle the Popup Menu with a middle click, and move my mouse off to the side to dismiss it, the Popup Menu disappears upon click, but it takes quite a few clicks to reactivate right clicks.
This is an old one, but I don’t see this issue here using the Rhino 6 for Mac beta. Please let me know if it’s still a problem for you.