RE: How do I intercept the Delete button in Manage on the ribbon?
Hello Miles,
In PO header, you have an option called "Customize Ribbon".
Right-click anywhere in the ribbon, that will show two options,
Collapse Ribbon
Customize Ribbon

Click the Customize option as shown above. It will open a new window,

In the New window, expand the manage option, then select the delete. On the right side, click the remove option and ok. Refresh the Navision. The delete will be removed from the Purchase order. You can use this to customize the fields in the ribbon.
I hope this helps.