I guess I'm not explaining myself clearly enough. When I say, "delete a track from the playlist," I mean in MC. Let's say I'm making a mix playlist. I make the mix in MC and synch it to my Zen. Then, later, I decide to take a song out of the mix. In MC, I go to the playlist, right-click the song, and choose Edit/Delete. Now the playlist doesn't contain the deleted song anymore. I haven't deleted the song from my library, just from the playlist.
Currently, if I synch the playlist again, MC will not update the contents of the playlist on the Zen. It will check to make sure that all the files are on the Zen. If "delete files" is checked, then it will remove the file from the Zen entirely (incidentally causing it to be removed from the playlist).
It seems to me that if I synch a playlist, then the contents of the playlist on the Zen should match the contents of the playlist in MC, regardless of whether I'm physically deleting files from the Zen or not.
Let me try one more example to see if I can make it clearer:
Playlist in MC: Song 1, Song 2
Playlist in Zen after synch: Song 1, Song 2
Contents of Zen hard drive after synch: Song 1, Song 2
Step 1: Add a song to the playlist in MC...
Adding a song works the way it should.
Playlist in MC: Song 1, Song 2, Song 3
Playlist in Zen after synch: Song 1, Song 2, Song 3
Contents of Zen hard drive after synch: Song 1, Song 2, Song 3
Step 2: Delete a song from the playlist in MC:
Okay behavior occurs with "delete" files checked...
Playlist in MC: Song 1, Song 2
Playlist in Zen after synch (WITH "delete files" checked): Song 1, Song 2
Contents of Zen hard drive after synch (WITH "delete files" checked): Song 1, Song 2
But what if I don't actually want to delete the song on the Zen, just remove it from the playlist on the Zen -- Problem behavior
Playlist in MC: Song 1, Song 2
Playlist in Zen after synch (WITHOUT "delete files" checked): Song 1, Song 2, Song 3
Contents of Zen hard drive after synch (WITHOUT "delete files" checked): Song 1, Song 2, Song 3
Desired behavior
Playlist in MC: Song 1, Song 2
Playlist in Zen after synch (WITHOUT "delete files" checked): Song 1, Song 2
Contents of Zen hard drive after synch (WITHOUT "delete files" checked): Song 1, Song 2, Song 3