Your comments

Well, it may be a good thing to have html export with MathML renderings.

Thanks - it's simple, when one exports the document in HTML, the math expressions should be exported in MathML <http://www.mathjax.org/demos/mathml-samples/>.

Thank you - so, the application should remain active after I close the last editor/viewer window, so that I can start a new one. Right now, when I close the last window, the application closes as well.