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SharePoint 2010 Ribbon and Quirks Mode issue

While working on upgrading a 2007 custom master page to 2010, I faced some challenges adding the new 2010 ribbon control to the page. A colleague of mine (Kevin) managed to pinpoint the issue and it tuned out that the master page was forcing the browser to render the page in quirks mode. When upgrading the master page make sure to add the <!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01//EN" "http://www.w3.org/TR/html4/DTD/strict.dtd"> to the beginning if its missing.

MSS2010PS90 Jan. 10 15.48
In Quirks Mode!
MSS2010PS91 Jan. 10 15.49 
Standard view (IE 8.0) after adding the <DOCTYPE> tag.