One of the most reported problems in feedback from my original HTML mock-up was Internet Explorer's inability to stop expanding the Learn page Inbox (a CSS element with overflow) with a left-right scrollbar. The underlying problem was that the width was being calculated as 100%, and then the scrollbar added on top. Mozilla browsers seemed quite happy to deal with this without bother.
After numerous hours of pondering and layering and stacking of elements, something seemed to work! This does seem to me to be a quite arbitrary stack of HTML and CSS, calculating away widths in their own special little ways.
<div class="containerbox"> <--- a seemingly pointless CSS class, but with width "auto"
<object width="100%"> <--- lets get HTML to do a width calculation too
Last but not least, my content here!
Why I need anything more than the original "inboxcolumn" CSS class I do not know, but mixing HTML, CSS with auto and percentage widths seems to do the trick.
Blimey – I could base my entire presentation just on this! ;)