I created a new panes view to see if that will fix the problem. Nope. Still the same behaviour.
Any tag entry e.g. genre, name, track #, disc #, artist, etc... standard or manually created, it doesn't matter. If you edit an entry, the locations pane resets or collapses back to root.
I think you may be thinking of the side tree's audio files view. I am specifically talking about the panes view where you add the file path field to sit beside the artist/album/genre/work/composer or whatever field you choose. It is convenient to use the location pane here instead of the side tree on the left. Why? Well, for one, activating the full tagging pane covers up the side tree completely. It's not as if the tagging pane can be set to appear on the right hand side of the window or even horizontally. That's the main reason why it's still such a bother to use it even if the side tree works okayish now.
*as for the playlist thing, I've yet found another similar solution for myself. I created a new custom field called EDIT. And added a single integer to set such (to be editied) files apart from the rest of my library. Instead of typing the longish full directory path in the search field I just write "edit=2" and this brings up the files that have yet to be tagged 100% correctly. I still have to use the tree view every now and then, but this makes it quicker rather than re-navigating all over again to the specific folder to be edited via the location pane. Again, if one uses the side tree -- or playlist view -- instead of the location pane, the rest of the panes in "panes view" (e.g. album/artist etc) will unfortunately always disappear. As flexible as JRiver is, it's still quite a long way from perfect. In fact, I still keep/prefer spotify and my NAS's built in music app on my phone at times -- and this having used JRiver software longer.