I have, for a long time, noticed the issue with hiding applications in Tiger, but I do not think it is new with Tiger. I believe it was the same with other versions of OS X. Further, I think this is not a bug but a feature (and an understandable one at that). I have found in the past that if I want to hide a number of applications quickly that I will press command-H multiple times until everything is hidden. Sometimes I will press command-H when the Finder is the active/in front application. This will hide all open windows in the Finder, but the Desktop will still be visible. Another application then becomes the in-front/active application. I am then unable to hide that application with command-H. Further, the hide command in the drop-down menu is grayed out. I would assume this is because it is not possible to have NO active/in-front applications. Some other application must always be "unhidden" to allow other applications to be hidden. Example: Right now I have half a dozen applications open. The desktop is active and I press command-H, which hides all open Finder Windows (e.g. "Macintosh HD"). I begin pressing command-H until I get to the point that the only application showing is Office Notifications (from Microsoft Office). I cannot hide that without "unhiding" the Finder. I click on the Desktop, thereby making the Finder active. This unhides any hidden Finder windows (e.g. "Macintosh HD"). I can then click on the Office Notifications window to make it the active application and then either press command-H or use the drop down menu to hide it. I hope I understood your problem and that the terminology I used was not too confusing. Ed O'Neal