IE9 -ms prefix not added for CSS 3 transform

[jvandenrym]

http://caniuse.com/#search=transform IE9 should support CSS 3 transform property if -ms prefix is added. Auto-prefixer seems not to add it. See the diff (.patch) and grunt options below.

.panel .back {
@@ -513,12 +514,16 @@
   z-index: 800;
   width: inherit;
   height: inherit;
   padding: 1em;
+  -webkit-transform: rotateY(-179deg);
+          transform: rotateY(-179deg);
-  transform: rotateY(-179deg);
 }

// Add vendor prefixed styles
    autoprefixer: {
      options: {
        browsers: [
        'last 2 version',
        'ff > 20',
        '> 1%',
        'ie 9',
        'ie 10'],
        diff: true
      },

[ai]

IE 9 doesn’t support 3D transforms, so Autoprefixer doesn’t add -ms- prefix for transform with 3D commands (like rotateY).

[jvandenrym]

Now I see ;) Auto-prefixer checks for 3d support. And IE9 has not got that for transform.