I have another dumb question about X2, "auto track zoom"

It is a per project and screenset setting so you can have different heights for both the in focus "zoomed" track and the out of focus tracks in each screenset and project.

Set them how you want them as and when required. It's not a one setting thing, which IMHO makes it far more usable.

HTH

Thanks. Just getting used to it.

 
I find it best to first set one track height for how I want Auto Zoom to see it, make that the only selected track, and then turn Auto Zoom on.   I've seen the "opposite behavior" thing a few times too where the Auto Zoomed track is minimized, but that's usually when I'm not watching what's selected when enabling it.