In my Music library, I have edited all of the KINK Radio Lights Out albums with the Label 'KINK Lights Out.'
In my Movies library, I've similarly added the label 'Oldies' to a few old movies.
When I go to either library (in fact, any library), click Filters>Labels, both the 'Oldies' and 'KINK Lights Out' labels appear in the list of labels. If I'm in the Music library, clicking the 'Oldies' label returns empty results, since the label belongs to movies. And, of course, if I'm in the Movies library, the 'KINK Lights Out' label gives no results.
At first I wasn't sure if this is a bug or a feature request. But then I realized that no other filter acts this way. I have Collections in both Movies and Music, but when I'm in the Movies library, only movie Collections appear in the filters list. In the Music libraries, only music Collections appear. Same goes for any other filters. With the exception of Labels, the only items that appear in the filters list are ones that pertain to the current library.
Labels should work the same way. When I'm browsing any library, only labels applied to items in that library should appear in the Labels filter list.