User-Agent: Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US; rv:1.8) Gecko/20051111 Firefox/1.5 Build Identifier: Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US; rv:1.8) Gecko/20051111 Firefox/1.5 A table with for example a margin of 10px and a border-width of 2px will be shifted 1px to the left and up. If a border-width of 4px is used, the table is shifted 2px to the left and up. The content that follows the table will also be shifted half the tables border-width upwards. Also, but this may be invalid, what color should the collapsed border be? should it be the color of the td or the table? should the color be that of the element with the largest border? Reproducible: Always Steps to Reproduce: look at the source of www.liquidia.be/test.html to check the CSS values used for the table and div's margins and borders Actual Results: margin-left of the table doesn't correspond with the margin-left of the div-element Expected Results: margin-left of the table and the div should have been equal.

as found on W3C : "Note only half of the two exterior borders are counted in the table width; the other half of these two borders lies in the margin area." Looking at the diagram under that line Firefox does indeed put the other half of the border-width in the table's content-width Seems this bug should be filed with Opera and Internet Explorer :-) Both these user agents do no put half the border-width into the margin-area.