Event.triggersContextMenu

This function returns whether a #GdkEventButton should trigger a context menu, according to platform conventions. The right mouse button always triggers context menus. Additionally, if [gdk.keymap.Keymap.getModifierMask] returns a non-0 mask for [gdk.types.ModifierIntent.ContextMenu], then the left mouse button will also trigger a context menu if this modifier is pressed.

This function should always be used instead of simply checking for event->button == [gdk.types.BUTTON_SECONDARY].