In our special application users can generate bookmarks like this
javascript:url="http://localhost:8080/superx/servlet/SuperXmlMaske?tid=17000&Kostentr%C3%A4ger=12080003&Kostentr%C3%A4ger-Sicht=Hauptsicht%20Kostentr%C3%A4ger&untergeordnete%20aufsummieren?=ja&Haushaltsjahr=2002&Zeitraum=monat%3E%3D1%20and%20monat%3C%3D1";%20if%20(window.oeffne)%20oeffne(url);%20else%20self.location.href=url;

it worked fine in Firefox 2 but in Firefox 3, I got an exception
reading window.document disallowed in dojo.js line 11958

I'm not sure what the problem was, but adding a try-catch seems to help