See example.
same problem with visible overflow, so floated parent has not correct width with floated childrens.
I believe WebKit's behavior is correct. Firefox 3 beta 4 behaves the same.
Currently Opera 9.5 (Mac build 4758) has the same behavior as Opera 9.27, Firefox 2 and MSIE7-.
Dupe of bug #16148 ?
WebKit agrees with all other browsers on the rendering here, (Chrome 20.0.1132.47, IE10, Opera 12, FF 15.01). I'm going to close this as invalid - feel free to reopen with some supporting evidence for the problem.