In previous Adobe Readers I have all open documents in a single window frame and can switch document with Alt-W or from the Window menu. Not so in Reader 9. I have compared Preferences with Reader 8.1.3 but not found an item that explains the difference.
Can I collect all documents in a single frame with Reader 9?
This change in behavior conforms to Microsoft's GUI for Windows. Why
Adobe is conforming now and not before I cannot say. Perhaps the GUI was
changed recently. In any case, if you do not like the new UI, please let
Microsoft know. Be aware, that this is the company that thinks the new
Office has a wonderful GUI.