How do I change the pitch of an orange track?

I have GarageBand '11, and OS X 10.6.8. I have an orange track that I want to change the pitch of, so I made it purple by holding control+option+g, and I clicked on the region. When I tried to move the pitch slider, it seems to be stuck. It's not greyed out or anything, it just won't move. What do I do?