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
{
		
		ElementPropertyDefn prop = (ElementPropertyDefn) getDefn( )
				.getProperty( propName );
		if ( prop == null )
			prop = getUserPropertyDefn( propName );
		return prop;
	}
	/**
	 * Validates that the given property name is either a system-defined or
	 * user-defined property.
	 * <p>
	 * Part of: Property system.
	 * 
	 * @param propName
	 *            The name of the property to validate.
	 * @throws PropertyNameException
	 *             If the property is undefined.
	 */
	void validatePropertyName( String propName ) throws PropertyNameException
	{
		if ( getPropertyDefn( propName ) == null )
			throw new PropertyNameException( this, propName );
	}
	/**
	 * Validates the given property value. Validation may map the value onto a
	 * new value that should be used for the actual property update.
	 * <p>
	 * Part of: Property system.
	 *