Not a bug IE10 Gradients

Here's an example of a simple CSS gradient:

    background:-webkit-gradient( linear, left top, left bottom, color-stop(0.05, #ededed), color-stop(1, #dfdfdf) );
    background:-moz-linear-gradient( center top, #ededed 5%, #dfdfdf 100% );
    filter:progid:DXImageTransform.Microsoft.gradient(startColorstr='#ededed', endColorstr='#dfdfdf');
As far as I'm aware XenForo creates browser specific CSS, for example one can use:

border-radius: 5px;
And XenForo will convert it to (as far as I'm aware):

border-radius: 5px;
-webkit-border-radius: 5px;
-moz-border-radius: 5px;
-o-border-radius: 5px;
The problem is that IE9 handles filter: without an issue, IE10 requires -ms-, especially for gradients. I have no issue using this for non XF content but it just simply doesn't appear to work on XenForo.

I tested this by creating a simple HTML page and using the same CSS as I've used within XenForo - HTML page works fine but XF doesn't.

Is this an issue or am I missing something somewhere? I've tried the CSS in EXTRA.css as well as in the extra area within the style configuration section.