It is often hailed that Firefox and Opera are “Standards Compliant Browsers”; even Internet Explorer is not bad most of the time. It is a little known secret, however, that they are only compliant when it suits them (and us).
When it comes to handling “CSS floats”, that is sections of the content that push to the left or right of the window and allow the remainder to flow around them, what they do is work out the size of the content of the float and then position it according to instructions. If you don’t specify a width for the container then it is determined by the width of the content. This is what designers like as it allows them flexibility and a fluid layout.
However the Standard says
A floated box must have an explicit width (assigned via the ‘width’ property, or its intrinsic width in the case of replaced elements)
Only Internet Explorer on the Mac obeys this rule and creates havoc with some styling. Now this browser is dying out rapidly, it went out of development in Jun 2003 and out of support in Dec 2005, but it still lingers on, especially among genealogists it seems.
Yes, we can hack around it but that is not the issue. If we want the design that we are used to, then the standard needs to be changed, otherwise we tempt anarchy.