Add 'right click' capabilities to dropdown list (VBA)

I have created a DropDown List in VBA(Word) via the ".Controls.Add(Type:=msoControlDropdown)". I have assigned an "OnAction" pointer, but it fires only when the left mouse button is clicked. I need 'right click' functionality, if possible, for when if a user right-clicks on an item in the dropdown listing.

Am looking for addition to or alternative to msoControlDropdown that would give me this functionality.

Please write for clarification.