Let users drag and drop object(s) on the custom animation order list to add them to the list at the drop position.
Example list with these items:
aaa (start on click)
ddd (start on click)
Dragging and dropping object ggg on bbb would add ggg to the list at that position.
This feature is still missing in 18.104.22.168
*** This bug has been marked as a duplicate of bug 37483 ***