hmm, if it's working in CS5 for you Roland, than maybe I need to reinstall. I'm on Windows XP, double clicking on the application window (area where documents windows go) still works (not so useful when I have a document open), but double clicking under the tools panel (single column) isn't working. I'm in the habit of double clicking there all the time, so it must have worked in CS4. I'll have to remember to try on my machine at home later.
And I'm still hoping an update/upgrade will give us the Window>Show/Hide Panels menu when right clicking in the dark grey area where panels get docked so I have quick and easy access to all the panels right where I dock them. Seems so obvious and intuitve that I keep trying that as well, but it's never worked. Add to that wish list, the ability to doc other panel icons below the Tools panel. I'd love to be able to store Libraries or other lesser accessed panels there. ANy one else have the same wishes? Submit to Feature Request!