Adobe InDesign CS3 or CS4 fails to respond to the show or hide commands when you use the Cmd+H keyboard shortcut or the "Hide InDesign" or "Show All" commands on the Application menu on Mac OS X10.5.x.
InDesign may enter into a hidden state and cannot be made visible again. This can occur when switching context from or to InDesign. For example, clicking on the desktop to switch to the finder, or using the Command+Tab keys to switch between InDesign and another application.
You might also have problems maximizing or minimizing the application.