I’m having a weird problem that I wasn’t even sure how to search for an answer.
Basically, if I view my site in IE9 using a localhost URL, it renders perfectly.
(example: localhost/site/index.html)
But, if I view that exact same page, still running on localhost using IIS, but with the fully qualified URL, IE9 seems to ignore several CSS selectors, specifically anything that uses CSS3 like rounded corners and box shadows.
Since the qualified URL is considered to be within my local intranet, IE by default renders the site in ‘compatibility mode’ so I was seeing the lack of CSS3 features supported.
Disabling this option allows the site to render properly, although this seems like a big issue for people who develop solely for intranets. Our current development site is all technically on an intranet, so the site won’t look correctly to stakeholders unless they disable this option too.