Lines Cause Viewing Problems When Editing in Firefox Viewing in IE

I was using Firefox to edit my Wiki however when co-workers viewed it in IE 6 it did not display properly. The "insert lines" are slightly wider in Firefox and when viewed in IE it caused the home page to not view next to the side bar. The home page content started just below the side bar so that the lines could display accross the page. Maybe a slight adjustment to the width of the "insert lines" would correct that problem.