|Microsoft DirectShow 9.0|
Signals that either the number of available buttons changed or that the currently selected button number changed.
DWORD value indicating the number of available buttons.
DWORD value indicating the currently selected button number. Selected button number zero implies that no button is selected.
Button numbers range from 1 to 36.
The currently selected button can change automatically with a navigation command authored on the disc as well as through application control by using IDvdControl2 interface.
This event can signal any of the available button numbers. These numbers do not always correspond to button numbers used for IDvdControl2::SelectAndActivateButton because that method can activate only a subset of buttons.
This event is raised in all domains.