FC3: Gnome, Applications Menu, panel properties not modifiable

[A1tmblwd netscape net]

I installed the Mozilla Web Browser but didn't find a launcher entry
in the Gnome Desktop when I clicked on Applications --> Internet.  So
I did some searching, located the file
/usr/share/applications/mozilla.desktop and changed the parameter
"NoDisplay=true" to "NoDisplay=false".  That fixed the problem with
Mozilla not appearing in the menu. I noticed, after making the change, 
that the controls in all of the panels within the Applications Menu are 
disabled. For example, when I right-click on "Firefox Web Browser" and 
select Properties the controls in the Basic and Advanced tabs of the 
Launcher Properties box are all greyed-out/disabled.  All of the 
launchers in the Applications Menu are similarly effected. With FC2 
Firefox and Mozilla were both visible in the Internet folder and I was 
able to change icons, descriptions, etc.  What changed in FC3 and what 
do I need to change to get this feature back?

Thanks,