The Devices -> iPhone -> Sync Apps tab is greyed out / foggy / not functional.
It does not let me check / uncheck the box. All the other tabs like Summary / Info / Music etc work normally
When I sync with my iPhone 4 it does not sync the Apps but all other information / music / data gets transferred.
All the Apps are shown under the Library -> Apps screen and also visible in the greyed / foggy area screen on the right side under the iPhone picture box
I have restored my iPhone - it does not work.
I have no restrictions set and have started / restrated iTunes - nothing works.
iTunes 10.2.2.14 and iPhone 4 iOs 4.3.5
I found the answer here: https://discussions.apple.com/message/15129510#15129510
"Is your computer authorized: Store>Authorize this Computer? Apps restricted in parental controls: iTunes>Preferences(under the edit menu if using Windows)>Parental? Restricted on your phone: Settings>General>Restrictions(are they on?)>Installing Apps>Off?"
Restrictions was on in my iPod. As soon as I turned that off, every was good to go.