When I put my Macbook Pro to sleep, the windows which contain open PDF files in Adobe Reader 9.3.3 disappear. All I can see are the title bars which would be located at the top of the window, with the close, minimize and maximize buttons. I am using Snow Leopard (10.6.4). This only happens with Adobe Reader. Preview works as expected, and so does Adobe Illustrator.
This bug has been present ever since I started using Adobe Reader in Mac, probably in 2006. Wake up guys!