Bug 119566 Support template items in page header/footer
Currently you can't create template report items inside a page header/footer. This should be fixed.
model/org.eclipse.birt.report.model/src/org/eclipse/birt/report/model/core/DesignElement.java
ElementRefValue ref = resolveElementReference( module, prop );
		return ref.isResolved( );
	}
	/**
	 * Returns the list of elements that extend this one.
	 * 
	 * @return the list of elements. The list is always non-null.
	 */
	public List getDerived( )
	{
		if ( derived != null )
			return new ArrayList( derived );
		return new ArrayList( );
	}
	/**
	 * Returns the valid status of this element. Child elements need to
	 * overwrite this method to say in which condition they can be said valid or
	 * not.
	 * <p>
	 * for example, if a JDBCDataSource can not reach the server, then it's
	 * invalid.
	 * <p>
	 * UI needs this method to show different icon for each element in the user
	 * interface.
	 * 
	 * @return true if this element is valid, false otherwise.
	 */
	public boolean isValid( )
	{
		return isValid;