Menu manager: easier to move item from secondary to dropdown

[TSP]

Could you make it easier to change a menu item to utilize the submenu-approach to change it to be a dropdown-menu?

Currently if I wish to do this, I have to:

1. Change to dropdown for the menu item
2. Delete all previous menu items under the secondary menu
3. Manually create the very same menu items I just deleted by clicking the dropdown-button for the item

There should be an easy way to move these / do this in all one swoop.