Ok, I've confirmed both bugs.

The popping I hadn't noticed before. I think that it is a symptom of the low Q value, pushing the band affected below DC. (In theory anything below Q=0.5 does that). This DC offset should be filtered out in the analog output stages (though AC coupling capacitors), so it shouldn't be a problem wrt to amps or speakers, but the transition between one DC level and another is causing a sharp transient that would get through the filter.

I originally had an explicit 0dB setting, with "Off" appearing as the setting below -6dB. Maybe we'll have to revert to this to remove the popping. (We need the "Off" setting so that users who don't want to use this feature don't get their eqs overloaded.)

The DC-mode non-restore I'll have to look into. I saw it in some of my test builds, but not in the patch that I eventually submitted to Mark. I never got a clear understanding as to what changed to fix it in my builds, and I can't see how Mark's changes would have affected it either...so. Debug time.