OptionalonOptionalonCalled when the user picks "Find Shortest Path" with two nodes selected. The toolkit emits the source/target; you decide what the secondary view does with it.
OptionalonCalled when the user picks "View Neighbors" or "Focus N-hop". Receives the subgraph UGM ready to render in a secondary view.
Called when the user picks "Edit Appearance" on a node. Open the NodeStyleEditor in your application.