Why does the audio volume alter when the window is switched between "Full screen", "TV window" and "Normal"?

Same key on RC?

I have found that it only does this after I minimise ProgDVB. It must be a bug in the mute on minimise routine?
For me ProgDVB has a few problems but I still love this program. Keep up the great work.

You can change that in Settings.

I think we have a little bit of a misunderstanding.
If I have the "mute on minimise" enabled this is what happens-
I start with a normal window, volume is set to 80%
I now minimise the window, now volume is at 0% (fine so far)
normal window again, and now the volume is at 30% and I have not adjusted the volume, it should still be set at 80% or any other level it was set to before the minimise?

Checked. No problem on my PC.

are you set to default directsound device?

Yes. But this is interface function and not depended from renderer.

OK once ProgDVB has been minimised (because it only does this after it has been minimised) try switching between "Full screen", "TV window" and "Normal" and see if the volume is still as you set it.