One of the most annoying bugs I have with Android... No option to change this.
The volume buttons/rocker on my phone does not allow me to change to media only. If no media is playing it only changes the ringer volume.
Imagine this setting, in my car I have volume all the way up, I get out of car and put on headphones, volume is too loud. I ether play music to where my ears bust or I go into settings and change the volume there. When I try to turn it down immediately, it changes the ringer until I let that volume display disappear. Which means I'm stuck listening to it too loud until I let it disappear to where I can change the media volume.
My little rant is over, how do I force the volume buttons to only be media! FOREVER!