add to collection indicator, when item already present
When I drag an item from a list to a collection, if the item is not already in the collection I see a + sign in a green circle. If it is already in the list, there is no sign. This is problematic because, with a large set of targets (collections, sub-collections) to drag to, successful targeting of the drag & drop operation can be uncertain. Am I getting no indicator because the item is already in the collection - or have I missed the target? A different indicator that I've hit the target would be a welcome enhancement. Maybe a + sign in a yellow circle?