Wouldn’t it be nice to use html5 and css3 in SharePoint? No problems, there is actually v5 master out there, created by Kyle Schaefer. Or just use h5ml5 and css3 right away in your webparts and pages. But there is a big problem. It doesn’t work in IE9–. One of the issues (even listed by Kyle) is that “save” doesn’t work in modal dialogs where Rich Text Editor is used. Especialy it is for modal dialogs.