Just had a quick look at the Mozilla ActiveX project was last updated in 2005 and is now a dead project.
http://www.rj-texted.se/ has some how managed to embed both Firefox and Chrome as internal preview engines but looks like he had to include a lot of the dependencies with it. -- Carbonize <http://forum.pspad.com/read.php?2,57537,57543> PSPad freeware editor http://www.pspad.com
