Volume buttons while screen off

[Unknownforce]

So, when I am using my phone for music, (using the standard Manila player or any other player for that matter) the volume controls do not work while the screen is off... I seem to remember this working this way before... I flash my phone regularly... So I think it's probably a setting I'm missing or that has been disabled in the rom that I use...

Is this a registry setting or something? I DON'T want it to turn the screen on, just control the volume...