[thincom2000]

This occurs only in Internet Explorer 9 beta when using a Document mode that doesn't match your Browser mode. This causes problems parsing the Internet-Explorer conditional tags because the browser now has 2 conflicting version numbers.

Make sure the Developer Tools menu is open when you are changing versions and you'll see that the option "Force IEx Document mode" doesn't change the version numbers correctly. You want to change both versions from this toolbox together.

I think the Document mode affects DOM parsing, and the Browser mode affects CSS/JS parsing. If these two numbers are out of sync, then yes, you will have problems.

If the Document number is too high, conditionals for style (CSS) tags that only affect IE7 won't parse.
If the Browser number is still IE7, then it will follow IE7 CSS rules, but doesn't have them because the style tag wasn't parsed.

If the Document number is too low, conditionals for style (CSS) tags that only affect IE7 will parse.
If the Browser number is still IE9, then it will follow IE9 CSS rules, but the IE7 rules were loaded above, and IE7 CSS is "broken" in non-IE7 Browsers.

This isn't something VaultWiki has control over, it's just something you have to keep an eye on when you're messing with your Debug menu.