Using my slingbox 500, which is connected to a Directv HR24 receiver, running Slingplayer on the Amazon Fire stick, the - (dash) button on the remote control interface does not work.
I had this same issue on the Android app a while back. I called support about that one and they sent it to the programmers and an update to the app fixed it. A similar update needs to be issued for the Amazon Fire Stick Slingplayer app because there is no - (dash) on the Directv on screen remote interface. There is a . (dot) but the dot does not do anything when you click it. This makes it impossible to change the station to any station that has a - (dash) in the station number (which is a lot of them on Directv).
This is a bug in the software. Can someone please report it to the appropriate groups. It looks like I have to pay $30 in order to call support, even though this is a bug in the software and not my issue.