In Tiger, Help Viewer was just another application. You can rearrange the help window just like any other application's window, putting it in the background or flipping back and forth to it. In Leopard, however, the help window floats above all other windows. This means that it always blocks whatever is underneath it, which is often the very window you need help with. There's no way to put the help window in the background. It's even worse if you switch to another application. If I open Safari's help window, and then I switch to Mail, Safari's help window is still there, blocking everything! I don't want to see Safari's help window on top of Mail.app.