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Yes it was (is) in Tools > Options > Options, but I was looking for a way to add the Validator to the horizontal display of features in the Web Developer tool bar.
I had to use Firefox's View > Toolbars > Customize and drag'n drop Tools on the Web Dev tool bar. This now gives me the validator drop down list that automatically loads the URL I'm currently viewing. The other way, I had to manually cut'n paste the address into the utility.