Thanks, Zybex. I have returned to using the Files view. I can't seem to find how to add the Track # to a list. I've seen it before but can't get back to where you can edit columns in Files view. That would be helpful.
Not sure, it could be that when I was trying to sort out another, still-unsolved problem - that of getting JRiver to recognize the retagging I had done (which I did outside of JRiver, using dbPoweramp), To do so, I first tried Configure Auto Import, as I noticed that the two big folders I had set up the library initially with were not in the list of folders that JRiver could see - probably because I had used the option "Import a Single Folder" and imported my two folders that way, rather than use the Configure Auto Import option initially. Then, I used the Run Auto Import Now option a few times, trying to get my tag changes recognized in JRiver (in vain, alas). Maybe that's where the over-population problem came from(?)
Now if I could just get those track numbers into the Files view, I can ignore the Player view, I guess. Still mulling over the tag-update problem.
Thanks very much again for your reply!