Table Header Misaligned in IE11 with scrollX

mrdata

To reproduce the issue:

1. Open Internet Explorer 11
2. Go to https://datatables.net/examples/basic_init/scroll_x.html
3. Press F12 to open the Developer Tools
4. Add a 1px border (e.g. table thead th, table tbody td { border: 1px solid } )

Note:
* The issue only occurs in IE11 with scrollX (we are ok with Google Chrome).
* The issue can be reproduced using the basic init version (i.e. no additional css or js)