Well, it’s totally doable. But it seems to make sense to have the
auto as AudioParameterBool.
You don’t need a button on the editor, the parameter would just expose that bool setting to the host. But TBH from a marketing and UX perspective, the auto button should deserve some visibility, who would know, that right click do something on the knob…
If you still want that to be handled by right click, you will have to override the enablementChanged() callback, since there is no listener callback for that.
Then you need to call beginGestureChange() before sending the new bool value and a endGestureChange() afterwards, and hope that it works in the host of your choice. Some are picky, when it is all sent at the same time, but I think there was a fix lately.
And when the editor is created, you have to set the slider’s enabled accordingly.