Scrolling does not work in Mail
Since I upgraded to Mavericks, the scrolling with my mouse or the arrow up/down keys on my keyboard do not work while within a long mail message.
Even if I click in the far right margin below the scroll bar to move to the bottom of a long message, it will not work. I must hold and drag down the long vertical bar on the right in order to see the rest of the message.
OS X Mavericks (10.9)