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/Module.java
{
		return validationExecutor;
	}
	/**
	 * Adds one validation listener. The duplicate listener will not be added.
	 * 
	 * @param listener
	 *            the validation listener to add
	 */
	public void addValidationListener( IValidationListener listener )
	{
		if ( validationListeners == null )
			validationListeners = new ArrayList( );
		if ( !validationListeners.contains( listener ) )
			validationListeners.add( listener );
	}
	/**
	 * Removes one validation listener. If the listener not registered, then the
	 * request is silently ignored.
	 * 
	 * @param listener
	 *            the validation listener to remove
	 * @return <code>true</code> if <code>listener</code> is sucessfully
	 *         removed. Otherwise <code>false</code>.
	 * 
	 */
	public boolean removeValidationListener( IValidationListener listener )
	{
		if ( validationListeners == null )
			return false;