DIV Tag deleted in IE when h1 is inserted

[Kerbetz]

Just use the demo site:
1.click "source code"
2.insert on first position <div id="news"> (just as an example)
3.insert on last position </div>
4.switch back to WYSYWIG mode
5.insert or add somewhere any text, mark it as headline 1 (or 2,3,4...)
6.if you look at the sourcecode now the DIV tag has been removed (begin and end tag)

The problem only exists for IE (tested on IE 6 - Version 6.0.2900.2180 only)

In FF it works fine (tested on Version 2.0.0.3 only)