Grx.ButtonEvent.type
ButtonEvent.type: Grx.EventType (Read / Write)
@GRX_EVENT_TYPE_BUTTON_PRESS, @GRX_EVENT_TYPE_BUTTON_RELEASE or @GRX_EVENT_TYPE_BUTTON_DOUBLE_PRESS
ButtonEvent.type: Grx.EventType (Read / Write)
@GRX_EVENT_TYPE_BUTTON_PRESS, @GRX_EVENT_TYPE_BUTTON_RELEASE or @GRX_EVENT_TYPE_BUTTON_DOUBLE_PRESS