macOS Dragging in Outlineview

[i.yalovecky]

How i can implement dragging highlighting (blue line) in case then i drag top level item that can be dropped only at the top level.

Example is Mail. When i dragging MAILBOXES it highlights where it will appeared very good for me.

 

[i.yalovecky]

This function setDropItem:dropChildIndex: helped me.

 

[GorillaPaws]

As you've discovered, use the delegate methods. The tricky part about drag/dropping using an NSOutlineView is figuring out the indexing, because the index is used in relation to the parent node, not to the global list. If you're trying to maintain sort order it can be a bit messy.