Hitting the back button after previewing a change to a wiki page results in the change going away, in IE.
Steps to reproduce:
1. In XWiki, through MS Internet Explorer, Click "Edit this Page" on any page
2. Add a line at the top
3. Click Preview
4. Click the browser's Back button
The line you added in step 2 is gone.
This appears to be counter to the default behaviour in IE. I made a test page with a <textarea>, and IE doesn't whipe out the text when I go to another page, and then back. I added the default xwiki meta header tags, thinking that might be the culprit, but that doesn't have any affect.