If you do a "Search by Title", it's searching only in the song titles stored in the MP3 tags themselves. If you do a "Search by Album", it's searching only in the album titles stored in the MP3 tags. Same for artist, year and genre. It's not searching for playlists, it's searching for songs, and looking at the tag data to do it. So, if you want to use those features, you have to make sure all your tags are filled out ahead of time.
There might be one exception... I haven't used the Empeg this way, but it's a shot: You are allowed, in Emplode, to fill out tag data for the playlists the same way you fill out the tag data for a song. If you filled out that stuff, perhaps the playlist would appear in those search boxes, too. I don't know, I always left that stuff blank in the playlists.
The reason it doesn't search on the playlist names is because it wouldn't know how to classify them. Are the playlists named after the artists? The genre? The album titles? Are the playlists named something arbitrary that has nothing to do with any of those things?
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Tony Fabris