I've been having trouble getting a mobile-friendly layout to work for a client's site. My browser loads every single style sheet, save MYTHEME-alpha-default.css.

I've checked the style sheet's URL, I've toggle the responsive grid on and off, as well as every checkbox underneath it, and found that the cause is probably malformed markup being generated by the omega theme.

In the source code below, you'll see that every media query floows a closed if ..IE9 statement -- except for the first one:

	<!--[if (lt IE 9)&(!IEMobile)]>
<style type="text/css" media="all">@import url("http://MYSITE.com:8080/sites/all/themes/MYTHEME/css/MYTHEME-alpha-default.css?mhtdf5");
@import url("http://MYSITE.com:8080/sites/all/themes/MYTHEME/css/MYTHEME-alpha-default-normal.css?mhtdf5");
@import url("http://MYSITE.com:8080/sites/all/themes/omega/alpha/css/grid/alpha_default/normal/alpha-default-normal-16.css?mhtdf5");</style>
<![endif]-->

<!--[if gte IE 9]><!-->
<style type="text/css" media="all and (min-width: 740px) and (min-device-width: 740px), (max-device-width: 800px) and (min-width: 740px) and (orientation:landscape)">@import url("http://MYSITE.com:8080/sites/all/themes/MYTHEME/css/MYTHEME-alpha-default.css?mhtdf5");
@import url("http://MYSITE.com:8080/sites/all/themes/MYTHEME/css/MYTHEME-alpha-default-narrow.css?mhtdf5");
@import url("http://MYSITE.com:8080/sites/all/themes/omega/alpha/css/grid/alpha_default/narrow/alpha-default-narrow-16.css?mhtdf5");</style>
<!--<![endif]-->

<!--[if gte IE 9]><!-->
<style type="text/css" media="all and (min-width: 980px) and (min-device-width: 980px), all and (max-device-width: 1024px) and (min-width: 1024px) and (orientation:landscape)">@import url("http://MYSITE.com:8080/sites/all/themes/MYTHEME/css/MYTHEME-alpha-default.css?mhtdf5");
@import url("http://MYSITE.com:8080/sites/all/themes/MYTHEME/css/MYTHEME-alpha-default-normal.css?mhtdf5");
@import url("http://MYSITE.com:8080/sites/all/themes/omega/alpha/css/grid/alpha_default/normal/alpha-default-normal-16.css?mhtdf5");</style>
<!--<![endif]-->

<!--[if gte IE 9]><!-->
<style type="text/css" media="all and (min-width: 1220px)">@import url("http://MYSITE.com:8080/sites/all/themes/MYTHEME/css/MYTHEME-alpha-default.css?mhtdf5");
@import url("http://MYSITE.com:8080/sites/all/themes/MYTHEME/css/MYTHEME-alpha-default-wide.css?mhtdf5");
@import url("http://MYSITE.com:8080/sites/all/themes/omega/alpha/css/grid/alpha_default/wide/alpha-default-wide-16.css?mhtdf5");</style>
<!--<![endif]-->

My guess is that if Omega used <!--[if (lt IE 9)&(!IEMobile)]><!--> for the first if statement, Chrome and Firefox would be able to read the different style sheets.

I'm also not able to see any of the responsive style sheets in IE10.