In order to differentiate between, say, an address book button and a browser button on the start menu toolbar at the bottom of the screen, the mozilla icons should be colour coded. This way you can easily tell if a button will open an email message or the address book or the browser window or whatever.

The problem isn't lack of whatever color... but that the same icon is currently used for all windows. Resolving as dup of bug 73712. *** This bug has been marked as a duplicate of 73712 ***