Perhaps you remember the
Dom Inspector in Mozilla which you never used, but thought might come in handy one day. Now there is this one problem where you would need it, but is gone. Gone? Well, at least on Windows you need to explicitly request it while installing, or you won't get it.
Ok, you now know that you made a mistake, but how to proceed? Do you really have to deinstall and re-install Firefox?
Well, that's the official position, but of course there is a way around:
C:\Documents and Settings\<username>\Local Settings\Temp\<random>.tmp\which is the place where the installer unpacks to.
adt.xpiinto your Firefox window, to install the Dom Inspector.
After you exit and restart Firefox, the DOM Inspector is now available as
Tools > Dom Inspector. Have Fun,