Lots of people need to implement right-click context menus for
TreeView's so we will explain how to do that here to
save you some time. Apart from one or two points, it's much the same as a
normal context menu, as described in the menus
chapter.
To detect a click of the right mouse button, you need to handle the
button_press_event signal, and check exactly which button
was pressed. Because the TreeView normally handles this
signal completely, you need to either override the default signal handler in a
derived TreeView class, use connect_notify()
or use connect(slot, /* after= */ false).
You probably also want to call the default handler before doing anything else,
so that the right-click will cause the row to be selected first.
This is demonstrated in the Popup Context Menu example.