Same problem here, as an (ugly) workaround i replaced every '1600px' occurrence, here:
[APPLICATION_SERVER_DEPLOYMENTS_PATH]/drools-guvnor/org.drools.guvnor.Guvnor/
If you are on a unix environment you can try something like this:
find ./ -type f -exec sed -i 's/1600px/800px/' {} \;