I have a first generation iPod touch running 2.2 and noticed this awhile ago.
1) Take your finger and slide half way to go to a different home screen.
2) Keep it there and then take your other finger and touch one of the apps in the dock and it should stick
1) Take your finger and slide half way to go to a different home screen.
2) Keep it there and then take your other finger and touch one of the apps in the dock and it should stick