Thank you for the nice app. I am sorry if this was already asked for but I could not find it.
I noticed that you can still see non-cached files in playlists that contain some cached files when in offline mode. I think it would be much easier to navigate these playlists if the non-cached files were greyed out. Maybe one could also darken the images as well.
Basically, just like Spotify shows files that are currently not available.
When in offline mode all playlists that contain cached files show up. Some of these playlists might also contain non-cached files. Those show up in the playlists as well. It can now be very complicated to see which files can actually be played and which cannot.
Easier navigation of playlists in offline mode
Spotify has such a system to show which songs are available and which are not. (see screenshot)