When using the combination of drools-guvnor and jBPM-designer on JBoss in IE 9 new diagrams are not loaded after creation

I want to use the jBPM Designer to create a BPMN2 process. It is in fact created (It is listed in the according package afterwards.) but when the new process should be opened and it's diagram be shown the screen remains stuck on showing the message "jBPM Web Designer loading. Please wait...". The same is true when I try to load existing BPMN2 processes from the repository (which I created using Firefox).