ITunes Not Allowing Additional Songs on Existing Playlists After Latest Update

The latest update to iTunes fixed a couple of problems (like the limit on the number of songs in "Played Recently) but it has created a new problem. My Playlists are still listed to the left of the iTunes screen, but when I right-click the three dots to add a song to an existing playlist, the only "Add to Playlist" option is "New Playlist." Same thing if I go to "Song" and try it that way. I can't be the only one with this problem. Who else is seeing it? DLS