Trim doesn't affect PFL channels

[cs-endo]

If you turn on the "PFL Channel" pro option and then change the trim level, the volume stays the same. The effect only appears when PFL is not enabled. I don't know if this is intentional or not but if PFL is supposed to mirror what goes out on air I think it makes more sense to have it register trim changes.

[mstratford]

So this is a technical limitation of the implementation, coupled with the (relative) simplicity aspect.

The PFL output is tapped before the gain node of wavesurfer, as such the fader volume doesn't affect the headphones.

To change this behaviour, the fader volume would have to be refactored to operate as a separate webaudio node, after the gain control.