How can

According to the developer tools in IE9 this CSS:

<link rel="stylesheet" type="text/css" href="one.css"> /*meyers reset*/
<link rel="stylesheet" type="text/css" href="two.css"> /*the main one*/
<!--[if IE]>
  <link rel="stylesheet" type="text/css" href="IE.css"> 
<![endif]--> 

is successful in that it results in the <link rel="stylesheet" type="text/css" href="IE.css"> being recognised/included. However neither the stylesheet not any of its declarations show in the tools/style panel. None of its declarations function.

How can this be?

I've tested the stylesheet is not functioning by changing e.g the color declaration.

IE developer tools show only the main stylesheet two.css and the meyers reset one.css working

one.css isn't actually listed but there's no word wrap for the CSS panel (only for the main/html panel) and the horizontal scroll bar doesn't reach the end of its declarations (!) so there's no room to actually display the filename.