Maybe you could try FireBox for displaying the actual web-pages, or try to work around their concept.
Which concept are you wanting?
I have no wish to make this addon a full fledged 'type in a URL' web browser.
The release says it has fixed scroll bars, and I might possibly look into that.
However, the notes later say, with big red sirens, "Don't message about scroll bars, I have no control over that".
Sounds like the author hacked his own for the main window, but couldn't fix Source's actual scrollbar issue.