Hi Ludek,
I got an e-mail notification of a reply from you, but I don't see it in this thread...
Anyway, I don't want to argue either, but you're writing about Internet Explorer, while I mentioned Internet Information Services version 7.5, two completely different things.
To answer your question, i tested the web app on the latest versions of Firefox and Chrome, and I got the same results in all of them. I didn't test IE yet, because the web app is based on html5, and IE does not support it well, as far as i know.