Bug 136241 [regression]Preview template in web viewer and pdf didn't get correct effect.
Description: Preview template items in web viewer and pdf didn't get correct effect. Steps to reproduce: 1. Create template items. 2. Preview in Web Viewer and pdf. Expected result: Same effect as in html. Actual result: In web viewer, see only blank box. In pdf, blank page.
model/org.eclipse.birt.report.model/src/org/eclipse/birt/report/model/core/DesignElement.java
* Inverse of the extends relationship: parent-->derived. Very few elements
	 * are extended, so we create this list only when needed.
	 */
	protected ArrayList derived = null;
	/**
	 * The unique ID assigned to this element when it is added to the design.
	 * Allows web applications to refer to the element by ID.
	 */
	protected long id = NO_ID;
	/**
	 * Cached element definition. Cached for speed since the definition cannot
	 * change.
	 */
	protected IElementDefn cachedDefn = null;
	/**
	 * Indicates whether the element is valid. The initial value is true.
	 */
	protected boolean isValid = true;
	/**
	 * API handle for this element.
	 */
	protected DesignElementHandle handle = null;
	/**
	 * The validation error list, each of which is the instance of
	 * <code>SemanticException</code>.
	 */
	protected List errors;
	/**
	 * Constant indicate that the element has no virtual parent.
	 */