NOTE: This one goes in the clearly 'experimental' category. I have not tried this myself yet, but the source (the X4U mailing list) is generally good, and it seems to make logical sense. Use at your own risk!!
Open a terminal session, and first navigate to the "Contents" folder of the application you'd like to modify (note - you may want to make a backup of the app first, especially if it's one of the Apple-installed applications). This example uses Key Caps:
cd 'Applications/Utilities/Key Caps.app/Contents/'Now, edit the Info.plist file:
vi Info.plistYou can use vi, pico, or emacs to do the editing.
Just before the closing Just before the closing </dict> tag, add
<key>NSBGOnly</key>Save the edited Info.plist, then launch Key Caps from the GUI (it's in /Applications). If your edit was successful, you should see the Key Caps window come up, but no icon in the dock.
<string>1</string>

