I'm using Marco, too, mostly because it's the default, and I wasn't aware there were options. I used the Compiz Config Settings Manager based on another website I read, or maybe somewhere else on this forum. It made the point that there are things CCSM can change, even if Compiz is not otherwise in use.
I didn't see the Reset Compiz button until just now when I tried Compiz for the window manager. I get the behavior I expect with Compiz. With other LibreOffice files open, when opening another, focus moves to the just opened file's window.
My recollection from a few years ago is that there was something about Compiz that I didn't care for. I don't recall what it was. But, since I get the behavior I expect with Compiz, I'll stick with it for now.
Thanks for helping me through this. I won't mark it as solved just yet, but will after I've lived with Compiz for awhile.