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
{
		ElementDefn elementDefn = (ElementDefn) getDefn( );
		List validatorList = ValidationExecutor.getValidationNodes( this,
				elementDefn.getTriggerDefnSet( ), true );
		ValidationExecutor executor = module.getValidationExecutor( );
		errors = executor.perform( this, validatorList );
		List list = new ArrayList( errors );
		int count = getDefn( ).getSlotCount( );
		for ( int i = 0; i < count; i++ )
		{
			Iterator iter = getSlot( i ).iterator( );
			while ( iter.hasNext( ) )
			{
				list.addAll( ( (DesignElement) iter.next( ) )
						.validateWithContents( module ) );
			}
		}
		return list;
	}
	/**
	 * Validates only this element without its contents, and return error list.
	 * The derived class should override this method to define specific
	 * validation rules.
	 * 
	 * @param module
	 *            the module
	 * @return the list of the errors found in validation, each of which is the
	 *         <code>SemanticException</code> object.
	 */
	public List validate( Module module )