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
* element inheritance hierarchy.
	 * 
	 * @param visitor
	 *            The visitor to apply.
	 */
	public abstract void apply( ElementVisitor visitor );
	/**
	 * Gets a property converted to a string value.
	 * 
	 * @param module
	 *            the module
	 * @param propName
	 *            The name of the property to get.
	 * @return The property value as a string.
	 */
	public String getStringProperty( Module module, String propName )
	{
		ElementPropertyDefn prop = getPropertyDefn( propName );
		if ( prop == null )
			return null;
		Object value = getProperty( module, prop );
		if ( value == null )
			return null;
		return prop.getStringValue( module, value );
	}
	/**
	 * Returns the value of the property in a localize format. Formats dates and
	 * numbers in the form according to the current locale. Converts choices and
	 * colors to their localized display names. Returns the localized display
	 * name for an element reference, etc.