warnIfDifferentRealms(realm, master.getRealm());
Assert.isNotNull(masterType, "masterType cannot be null"); //$NON-NLS-1$
IObservableValue value = MasterDetailObservables.detailValue(master,
BeanProperties.value(masterType, propertyName, propertyType)
.valueFactory(realm), propertyType);
return new BeanObservableValueDecorator(value, BeanPropertyHelper
.getPropertyDescriptor(masterType, propertyName));
}