Mendix does not recognize a XML element as nillable when referenced. Please look at the sample XSD: <xs:schema xmlns="http://schemas.datacontract.org/2004/07/XXX" xmlns:xs="http://www.w3.org/2001/XMLSchema" xmlns:b="http://schemas.datacontract.org/2004/07/XXX" targetNamespace="http://schemas.datacontract.org/2004/07/XXX"> <xs:element name="SomeElement" type="xs:string" nillable="true"/> <xs:element name="ComplexElement"> <xs:complexType> <xs:sequence> <xs:element ref="b:SomeElement"/> </xs:sequence> </xs:complexType> </xs:element> </xs:schema> When reading the XSD Mendix report the element "SomeElement" as nillable. But as part of the complex element "ComplexElement" it is reported as not nillable. We are now using references because there are multiple namespaces. Is there a workaround to let Mendix interpret this element as nillable?