I've found a serious problem with IE (7,8,9). The CMS WYSIWYG editor is not working. In IE7 and IE8, you don't have WYSIWYG controls at all and you can edit only the HTML code (even despite the WYSIWYG editor mode is checked). In IE9, the editor controls are shown, but you can't use mouse in the editor box (you can't even select text with mouse).
in CP06 the CMS WYSIWYG editor works fine for IE7 and IE8, with IE9 it has the same bug as (above) in CP07. thus this bug is a regression.