1:
When “Defined Menu” list has a scrollbar,
Drag and drop an item to move it.
Then move mouse (released) to the border of the list.
** The list will scroll.
2:
Select item A in “Defined Menu” list.
Drag item B.
** While B is being dragged, A is still highlighted.
This could be confusing.
3:
I think an empty Popup item should show the node image initially and always, otherwise it looks as same as a Command item but doesn’t respond to double clicking. it could make one confused for a while.