Hmm. Is it possible you're dragging the tracks into the Computer node rather than the Playlists node? I still don't know where the 200 file limit would come from, but that would explain why the file ended up in your playlist directory.
Edit: I see the screenshot, thanks. Yes, you're dragging the files into your Computer node, not the Playlist node. It may be possible to add files to playlists that way, but what happens if you use the Playlists node instead?
Edit2: What version of MB are you using? It looks like an older one - I suggest upgrading to 3.0 from the downloads page. In 3.0, I can't even see playlists in folders; I have to use the playlists node.