Allow items in a sortable container to move / sort into other lists but not starting list

[shanebruggeman]

My scenario involves a user with a list of created items on the left and an edit/create panel on the right. The user should be able to select a type of item to create from the panel and (with one click) drag that type into the item list on the left and place it in the position it should be in. However the types list in the panel on the right is not allowed to be reordered or altered. Before / after of dragging from the panel to the list should keep the panel in the same state.

Unfortunately, I've been unable to drop outside {{draggable-object}}'s into {{sortable-container}}'s. I think that's the subject of another issue that @boris-petrov mentioned here.

Likewise, I've tried keeping two {{sortable-container}}'s with the same sortingScope. But that allows items in the panel to disappear / reorder themselves. Could a flag be added to disable internal sorting of sortable-containers, and perhaps something to shallow-copy the dragged object into the receiving list, adding it to the receiving list but not modifying the list that owned the dragged object?