self. get_ selected_ device _num ("view. selected_track") returns -1 for first device in track

I have very simple script that outputs the selected_device_num whenever a selected device changed listener fires (self.song().view.selected_track.view.add_selected_device_listener)

When I select the first device it returns -1 as the index instead of 0. The second device returns 1 as expected

Script is attached.