I don't get it again

Extended my nanoEditor with a handle to drag, in order to resize the iframe used as edit area .
In Chrome and IE this works pretty smooth.
Demo page with sources here: http://hgsweb.de/nanoEditor

In some cases Safari, seems to pass back event.screenX/Y values way out of site, therefore the edit area
snaps to a size way to big. This happens in the ondragend handler.

However during the ondrag event the iframe is resized correctly, but not if the ondragend event is entered.

Firefox does not change the iframe size during the ondrag event but sets the
correct size when the ondragend event is fired.

Both , FireFox and Safar also seem to ignore the e.preventDefault() within the
ondrop event handler set on teh body of the iframe.

What am I doing wrong ?