[ScottiG]

Thanks to Seven Skins and Princeton for their replies!

After lots and lots of template checking and hair pulling, I finally found my problem... While the fix was not 100% directly related to the advice of either of those that offered suggestions, it "IS" because of their advice that I was able to eliminate a few possibilities and look a bit further up the chain to hone in on the problem, so my sincerest thanks goes out to you both for stepping up to the plate and taking a swing.

As it turns out, there happened to be a couple of lines of missing code in the "header includes" box in my current style - it was the CSS reference text to the editor_css - it simply was not there.

So, after hours and hours of tail chasing over the course of weeks, but now armed with the advice of those listed above, I finally got it working correctly!

Thanks again to Seven Skins and Princeton for your contributions!