"Select All From Here"- question

I haven't used the "Select All From Here (On)" function very much, but the few times I've experimented with it, it didn't seem to like locked tracks-- if a track were locked with material downstream "From Here (On)" it didn't seem to work.

Is that accurate? Or pilot error? I'd expect such a function to IGNORE locked tracks, but you never know.

Anyway, I'm now at the revision and deletion stage of an edit, and I've got a sound bed that I'd prefer to remain untouched by "Select All From Here (On)". Is that possible? Or does one use a different tool?

Thanks!