Shouldn't "display: table" act like other block display styles in that it should expand to fill the width of its containing block box? I realize that the current behavior probably needs to be retained for quirks mode, but it seems a better way of doing that would be to define table in ua.css as table { display: inline-table } table:before, table:after { content: "\A" }

No. The rules for widths of tables are different. See http://www.w3.org/TR/REC-CSS2/tables.html#width-layout In particular, the sentence "However, if the maximum width required by the columns plus cell spacing or borders (MAX) is less than that of the containing block, use MAX." Marking INVALID.

Okay, that's the part of the spec I was looking for when I submitted this but didn't find. Thanks.

Based on David's comments, marking as verified invalid.