[mathjax] long formula causes dialog window to go out of the viewport

[Wiktor Walc]

1. Make sure the browser width is like 1000px or so.
2. Enter the following formula in the mathjax dialog:

   x = {-b \pm \sqrt{b^2-4ac} \over 2a}{-b \pm \sqrt{b^2-4ac} \over 2a}{-b \pm \sqrt{b^2-4ac} \over 2a}{-b \pm \sqrt{b^2-4ac} \over 2a}{-b \pm \sqrt{b^2-4ac} \over 2a}{-b \pm \sqrt{b^2-4ac} \over 2a}{-b \pm \sqrt{b^2-4ac} \over 2a}{-b \pm \sqrt{b^2-4ac} \over 2a}{-b \pm \sqrt{b^2-4ac} \over 2a}{-b \pm \sqrt{b^2-4ac} \over 2a}{-b \pm \sqrt{b^2-4ac} \over 2a}{-b \pm \sqrt{b^2-4ac} \over 2a}{-b \pm \sqrt{b^2-4ac} \over 2a}{-b \pm \sqrt{b^2-4ac} \over 2a}{-b \pm \sqrt{b^2-4ac} \over 2a}
   

3. See that the Ok/Cancel buttons are unavailable.