I don't know why it worked, but here's what I did...
I'm using IE9 on Windows 7
Log out of DU
Click Tools, then Internet Options
Browsing history - Delete (note: "delete browsing history on exit" is unchecked)
Check Temporary Internet Files, Cookies, History
Log back in to DU.
"I hope we shall crush in its birth the aristocracy of our moneyed corporations which dare already to challenge our government in a trial of strength, and bid defiance to the laws of our country." --Thomas Jefferson