If you use an Inline Editor with quite a few tools in IE11 and use it on a fairly small box, the tools will not be on separate lines in IE11, so it will show a scrollbar to go to the right. But if you try to scroll to the right, the inline tools disappear. This causes any tools to the right to be unusable. See this example
(use IE11), based upon the Inline Editor demo on your site. It works fine in Chrome, just not in IE.