Our online wysiwyg editor that is used to create/edit webpages, newsletters, etc. has performance issues with IE 8 (XP and Vista).  The work around for this particular issue (at this time) is to turn on Compatibility View in IE 8. This switch (or button) is located just to the right of the address field in the browser.  When you are working on a webpage, newsletter, document, etc. make sure you turn Compatibility View ON by clicking the button.  This will allow your online editor to work properly in IE 8.  When you are finished with your work you can easily turn it back off.  Until there is a reliable patch available for the editor this is the best way to deal with the situation.