Using HM Professional v1.10 beta 5, I ticked Articles and Training > HM Forums and signed in. Of course, that launched the Interned browser and vBulletin® v3.8.4 software within which I'm now writing.
My OS is Windows XP SP3. Although I have IE8 installed, Mozilla Firefox is my default browser. Yet as I type this question, I cannot tell which browser I'm employing. Curiously, it resembles neither IE8 nor Firefox.
I hope that the source of my confusion makes some sense to someone. At any rate, thanks to all for taking the time to read my question.