Matt Neuburg’s top gripes about Leopard. I completely agree with him about the new Help Viewer window:
When you choose from the Help menu in any application, what opens is no longer the Help Viewer application. It’s an orphan window that floats over, and blocks your view of, everything else on the screen. It belongs to no application, so you can’t hide it or switch away from it. Now, what’s the most common thing to do while you’re reading an application’s help documentation? You read something in the Help, you switch to the application to try it; you see something in the application, you switch back to the Help to learn about it. No more. Now, as soon as the help window opens, you’re stuck: you’re in the help window and that’s the only place you can be, until you close the window (or minimize it into the Dock).