Can't drag songs in iTunes anymore.

I think the trouble started when I upgraded to Lion. It hasn't been a big hassle, but now I want to create a Christmas playlist to burn to a cd for my friends, and I just realized that if I can't drag, I can't rearrange songs within a playlist.

Details: no, it's not set to shuffle, and yes, the playlist is set to the "numerical" (far left column) sorting.

The weird thing is, when I first log in I CAN drag songs, but within a minute or so some unknown setting kicks in and it goes away. Very frustrating!