Playlists won't scroll at the "Sync Music" tab in iTunes 10.7.

I'm on a MacBook Pro Retina running Mountain Lion, iTunes 10.7 and syncing an iPhone 5 running IOS6.

I currently have 19 playlists and a total song count of 925 on my iPhone 5. I have a total of 92 playlists on my iTunes, but generaily have no more than 25-30 selected to sync at any one time. I have 9000+ songs in my library, and have "sync selected playlists, artists, genres & albums."

When syncing my iPhone 5, and select the music button, I get the windows for "Playlists, Artists, Genres and Albums", I cannot scroll past a list of 17 playlists filling the window, but cannot scroll down to see or select any playlists below the top 17.

This has been an issue since moving over from my iPhone 3g/iTunes 10.6. The playlists that synched and are "below" what can be seen, were moved over from the inital sync of the iPhone 5, but I cannot add anything below the visible list in the window.

Resizing or going to "full" on the window does nothing, except the scroll bar appears momentarily in the four windows but disappears very quickly, and the arrow keys only move me out of the "Devices -> My iPhone" list in iTunes.

Any assistance on a solution would be greatly appreciated.