IE10+ transform and position fixed problem

### BUG
In IE10+ elements inside the nav that are position:fixed do not shift when the side bar is expanded. This is a bug in IE 10+ only and works fine in all other browsers. You can reproduce this bug here http://codepen.io/miketierney/full/1d7ef66d650db41471532162b0b941af

You can also reproduce by making .container class position fixed in your official site http://plugins.adchsm.me/slidebars/ and open the sidebar in IE10+ and compare that with Chrome

### BUG FILED
The following bug has been filed and Microsoft has not fixed it since 2013 https://connect.microsoft.com/IE/feedback/details/806517/ie11-tramsform3d-and-position-fixed-problem