I dont test your issue, so I write this blind. If there is any mistake, forgive me.
I dont think about this as a flaw, because this has easy workarounds, simply handle the Click event and show the context menu by code instead of setting the ContextMenu property. Just one line! I don't think treeview has another way to get the selected node (I'm not sure).

Finally: God bless Metallica, James, Kirk, Lars and JASON