Bug 122850 Table/list should not be able to be inserted in Master Page mode.
Description: Table/list should not be able to be inserted in Master Page mode. Steps to reproduce: 1. New a report and transfer to Master Page mode. 2. New a datasource and dataset 3. Drag a list/table to page header/footer, bind it to dataset and drag some columns inside. 4. Save and preview Expected result: Insert list/table item in master page should be forbidden. Actual result: They are allowed and preview showed "undefine" in page
model/org.eclipse.birt.report.model/src/org/eclipse/birt/report/model/core/DesignElement.java
assert base.getDefn( ) == getDefn( );
			
			assert base.getName( ) != null;
			String namespace = null;
			Module root = base.getRoot( );
			if ( root instanceof Library )
			{
				namespace = ( (Library) root ).getNamespace( );
			}
			extendsRef = new ElementRefValue( namespace, base );
			base.addDerived( this );
		}
	}
	/**
	 * Returns the data set element, if any, for this element.
	 * 
	 * @param module
	 *            the module of this element
	 * 
	 * @return the data set element defined on this specific element
	 */
	public TemplateParameterDefinition getTemplateParameterElement(
			Module module )
	{
		ElementRefValue templateParam = (ElementRefValue) getProperty( module,
				REF_TEMPLATE_PARAMETER_PROP );
		if ( templateParam == null )
			return null;
		return (TemplateParameterDefinition) templateParam.getElement( );
	}