Usually there would be an 'angle' button on the remote for DVD players but depending on the DVD software you use, there should be a hotkey to assign for that button.
Movie DVDs do it too, but usually there's no indicator except on the boxart itself?
http://ahsforum.com/forum/showthread.php?t=101777
It looks like DOME TOUR had it as well for UNITE and Who... specifically?
http://www.ahsforum.com/forum/showthread.php?t=40839
CDL00-01 also has it on Trauma and teddy bear according to inserts.
It looks like for ct2000, the multi angle feature is lightly mentioned on the OBI!