A complex type can contain either:
        
            
                
                    - 
                        
simple content – character data or a simple type (but no elements), or
                     
                    - 
                        
complex content – elements or elements and character data
                     
                
             
         
        
            - 
                Open the property sheet of a complex type and select either simple or complex in the Content list.
            
 
            - 
                Click Apply to make available the Properties tool to the right of the list.
            
 
            - 
                [optional] Click the Properties tool to open the property sheet of the content, and specify an ID and, in the case of complex content, whether the content can be mixed.
            
 
            - 
                Click OK to return to the diagram.