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
* Part of: Property value system.
	 * 
	 * @param propName
	 *            The name of the property to set. Must be valid. Can be a
	 *            system-defined or user-defined property name.
	 * @param value
	 *            The value to set. Must be valid for the property.
	 */
	public void setProperty( String propName, Object value )
	{
		ElementPropertyDefn prop = getPropertyDefn( propName );
		
		
		assert prop != null;
		setProperty( prop, value );
	}
	/**
	 * Sets the value of a property. The value must have already been validated,
	 * and must be of the correct type for the property. The property must be
	 * valid for this object. The property can be a system or user-defined
	 * property. The value is set locally. If the value is null, then the
	 * property is "unset."
	 * <p>
	 * Part of: Property value system.
	 * 
	 * @param prop
	 *            The property definition. Must be valid. Can be a
	 *            system-defined or user-defined property.
	 * @param value
	 *            The value to set. Must be valid for the property.