A common Leopard-vs-InDesign complaint we hear from designers is not being able to hide InDesign, either from the InDesign menu or by pressing Command-H. And worse, if you can get InDesign to hide, you can’t get it back.
Happily this problem can usually be fixed by deleting the InDesign preference file.
The quickest way to delete InDesign’s preference file is to hold down Control-Command-Option-Shift when launching InDesign. You’ll get a dialog box allowing you to easily delete the preference file.
Or if you prefer, you can go into
~/Library/Caches and delete the contents of the Adobe and Adobe InDesign folders by hand. (Note: ~ denotes your User folder.)
Quit and relaunch InDesign, and the Hide option should work again.
Source: This tip written up in the May 2008 issue of Design Tools Monthly.