I am having an issue with my navigation buttons, page built using DW CS4.
It looks like the hight of the box is being doubled, works fine in IE8 and chrome etc.
I am aware of the double marging fix for floated with margins, is this similar?
Increase text size (zoom, text only) in a non-IE browser and see what happens to your page. Height property is a restriction in all non-IE browsers whereas IE treats height as if it were min-height.
My advice is to avoid using height values on content areas with text in them that could be increased in size depending on the site visitor's settings.
See also min-height: