Can't delete songs from iPhone manually

[magicrevolver]

I manually manage my songs and albums on my iPhone 4. However when I tried to delete some songs/albums, using the usual way I've been doing it by selecting the songs then hitting the delete key, it doesn't work. All that happens is iTunes scrolls to the last album (alphabetically) on my phone. There's no right click option to delete either. I've also noticed that the same happens if I try and delete anything from my iTunes library. If I hit the delete key the same thing happens, but at least I can right click and select delete in the menu.
I'm running the latest iTunes (10.4) on a macbook pro OSX Lion.
Anybody else had this?

 

[saturdaykid]

This describes by problem to a t. Also can't delete from iTouch or iTunes.