dragging music into iPhone from iTunes.

[mmedina4]

does anyone know why iTunes is not letting me drag and drop music into my iPhone anymore? I used to be able to, but recently I'd be able to drag it, but it wont show up on my iPhone. I do have the 'manually manage music and videos' box checked in the summary. and the iPhone is plugged in (fyi). but it's just not showing up on my iPhone.
- so in simple terms, how do i get the music i dragged in to show up on my iPhone again?

so please if anyone knows has information on why this occurring please let me know, it'd be greatly appreciated.