This is a W3c Standard for using <Colgroup> and <Col> for formatting table cells in the same column. http://www.w3.org/TR/html401/struct/tables.html But at this time, webkit only apply the width setting specified in the <colgroup> and <col>.
Could you please attach a test case that doesn't work as you expect?
Created attachment 88013 [details] test case Ah sorry, I've just noticed the link in bug URL, and that it's not the same as the link in bug description.
Attached test case seems to look same in Safari Technology Preview 186, Firefox Nightly 123 and Chrome Canary 123.