User-Agent: Mozilla/4.0 (compatible; MSIE 7.0; Windows NT 5.1) Build Identifier: Mozilla/4.0 (compatible; MSIE 7.0; Windows NT 5.1) Suppose we have a table of three columns. They have a common header cell spanning all three columns. Each column has an associated COL tag. The middle one has style attribute visibility: collapse. The header is then NOT centered across the two visible columns. It is rendered instead as if all three columns were still visible. Reproducible: Always Steps to Reproduce: <!-- Example --> <table border="1"> <colgroup> <col > <col style="visibility: collapse"> <col> </colgroup> <thead> <tr> <th colspan="3">Demo Table</th> </tr> <tr> <th>First col</th> <th>Second col</th> <th>Third col</th> </tr> </thead> <tbody> <tr> <td>1</td> <td>2</td> <td>3</td> </tr> </tbody> </table> Actual Results: Header cell is centered across all three columns, as if middle one were still visible. Expected Results: Header cell should only be centered across the two visible columns.