FCKEditor Icons appear lined up vertically along the left hand side of the page with IE 9 RC 1 on Windows 7 32 bit machines. Hovering the mouse cursor over the FCKEditor's toolbar brings the icon into view.
I activated the FCKEditor's about dialog, and the contents didn't display and I could not get the About dialog to go away.
Also, tried viewing FCKEditor in Sakai 2.6.x and IE 9 RC 1 Crashed. Didn't get a chance to test in 2.7.x