jackmoore/autosize — pull request #181 by hnguyen08 (2014-10-30 00:47:01+00:00)
Title: IE8: surrounding elements do not repaint to reflect new textarea height

If the textarea is found nested 2 or more levels inside an inline-block element, then the surrounding elements do not get repainted.

http://jsfiddle.net/e2scs4y3/5/

As the textarea expands, it expands without pushing the neighboring element down. Once the text is highlighted, then IE8 will trigger the repaint and render correctly. I think this is the same issue as described in http://blog.caplin.com/2013/06/07/developing-for-ie8-inline-block-resize-bug/.

I was able to fix it by forcing a repaint on the mirror, only when the textarea's height has been updated.