[curt.clifton]

The iPhone app has different behavior because it has been updated more recently. The Mac app will eventually behave like the iPhone app in this regard (optionally, I think). Until then, you can't change the behavior.

An interim solution would be to create a single action list specifically for "project-less" items. Use that list as the project for your items with a context and no real project. You'll have to treat that like a second inbox, but I don't see another work-around until Omni changes the app.