Ctrl+D inside a layer's sub-graph causes the parent layer to be placed inside itself

[Keavon]

1. Create a new document
2. Draw a layer
3. Open the node graph
4. Double-click the layer to enter its sub-graph
5. With no layers or nodes selected, hit CtrlD (CmdD on Mac)
6. --> The parent graph's layer, that we are currently viewing the inside of, has unexpectedly been duplicated into its own sub-graph!

capture_37_.mp4