SUMMARY *** When you right-click a folder, in addition to "Open File Manager here" and "Center Map Here", there should be an option for "Start a new Filelight instance here". "Center Map Here" is not good because when you try to go back up it takes forever to rescan the whole drive, so I'd rather just open a new filelight for each subfolder. ***
We hit hot caches when going back up, I fail to appreciate why it would be slow. In any case this seems an awfully niche use case.