// intercept the binding on the script so we can
// be notified of changes.
Map originalVMap = script.getBinding().getVariables();
originalVMap.put(SCRIPT_VAR, script);
ObservableMap obsVariables = FXCollections.observableMap(originalVMap);
obsVariables.addListener(instance);
Binding newBinding = new Binding(obsVariables);
script.setBinding(newBinding);
}
Property property = instanceMap.get(propertyName);
if(property == null) {