This is something I discovered when implementing Superfish on our recently redesigned site at http://www.ciu.edu.
We have navigation menus that are edited by content editors as html files. Our PHP files will include that html file if it exists. However, the WYSIWYG editor (XStandard in this case) inserts a HTML comment at the top of each file. When this file is included on a page that has a Submission form (in our case, a Preview Days registration form), and it is part of a submenu, it throws an error in IE. In IE8 (and compatibility mode of IE8), it degrades gracefully and shows a javascript error icon in the lower left corner. On IE7 and below, it pops up a javascript dialog box and sends the user away from the page, disallowing them to fill in the form. The error message talks of a HTML Parsing Error. I've traced the error message to a Knowledge Base article from Microsoft, in which it basically indicates that you have unclosed tags (which I did not). Then I traced the error to the comment being inserted by the WYSIWYG and found that if the HTML comment is past a certain amount of characters, then the insertion of the arrows by Superfish throws the IE error. I was able to solve my problem by just removing the HTML comment and the error went away. However, future edits on these navigation files will probably add the comment back in, over which I have no control over, with the exception of possibly writing a php or javascript script to look for the comment and manually remove it. I'm really just posting this as information for anyone who may run into a similar error. Maybe there's a solution within Superfish on this. I have not examined the code yet to see, but just wanted to put the information out there that this is a known bug in Internet Explorer and how to not cause the bug to happen.
