User-Agent: Mozilla/5.0 (Windows; U; Windows NT 5.0; en-US; rv:1.4) Gecko/20030612 Build Identifier: Mozilla/5.0 (Windows; U; Windows NT 5.0; en-US; rv:1.4) Gecko/20030612 In the uploaded testcase, in which there is a table with CSS property "border-collapse : collapse" encompassed by a div, the border of the parent element (div) is overwritten by the border of the inline (table) element. Reproducible: Always Steps to Reproduce: 1. View test case. Actual Results: Three sides of the border of the <div> are overwritten. Expected Results: The <div> and <table> borders should have been rendered separately. In 1.3.1, only the top and left borders were overwritten. In 1.4RC2, all borders except the bottom border are affected. This is not a duplicate of bug #196133, which was resolved.

The spec says that the outside borders of 'border-collapse' tables live half outside and half inside the table. That probably partly explains this...

Yep. There should be a 1/2px overlap between those two borders, if I read the spec correctly. We end up rounding that 1/2px to 1 at the top and left, 0 at the bottom and right....

Didn't intend to not respond for so long. No, you see, these aren't encompassing table elements. It is a <div> encompassing a <table>, the <div> does not have border-collapse set to collapse, and even if it did, it should not be combining with the table borders.

see http://www.w3.org/TR/CSS21/tables.html#collapsing-borders [quote] 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. [end quote] [quote] Note that in this model, the width of the table includes half the table border. [end quote]

Here is a testcase with margins set on the table. My guess is that mozilla's behavior can be considered standard compliant but doesn't look good. However it seems odd that the borders of the table lie in the margin for top and right borders but lie in the table for bottom and right borders. css2.1 says: [quote] User agents must find a consistent rule for rounding off in the case of an odd number of discrete units (screen pixels, printer dots). [end quote] Is Mozilla's behavior considered consistent? CSS2.1 says that half of the table border lies in the margin area. What about the case when there isn't a margin (attachment 1 [details] [diff] [review])? CSS2.1 also does not say anything about top and bottom borders.

Also, as of Moz1.4, the right border is also sometimes overwritten in the first testcase (resize your browser window).

This is indeed an issue in CSS2.1. See http://lists.w3.org/Archives/Public/www-style/2003Mar/0003.html *** This bug has been marked as a duplicate of 155955 ***