There's now way, if you don't want to get rid of your box set setup. The reason why it changes layout, is that some of your views have no series or box set meta data. Hence all movies will be shown at the file level. When suddenly two movies have the same Series or box set info, the movies are grouped by category, and you loose the file info.
This got a lot better with the Zoom function, that skips the unnecessary single item under categories. But the trade off is still the lack of the file info pane. I really how that JRiver can figure out a way to force the File info pane for items that is below a category. When there's more than one item, it could just show nothing, or a sort of summary. This is something that's not only limited to Movie Boxset setups. It's also needed for TV Show, Season, Artist, Album summaries.