Bug 179743 Parameter Validate Event is not Called
I have tested the validate event on parameters and it never appears to get called.
engine/org.eclipse.birt.report.engine/src/org/eclipse/birt/report/engine/api/impl/EngineTask.java
* 
	 * The locale must be called in the same thread which create the engine task
	 * 
	 * @param locale
	 *            the task locale
	 */
	public void setLocale( Locale locale )
	{
		log.log( Level.FINE, "EngineTask.setLocale: locale={0}", locale == null
				? null
				: locale.getDisplayName( ) );
		doSetLocale( locale );
	}
	private void doSetLocale( Locale locale )
	{
		this.locale = locale;
		executionContext.setLocale( locale );
		EngineException.setULocale( ULocale.forLocale( locale ) );
	}
	/**
	 * sets the task locale
	 * 
	 * @param locale
	 *            the task locale
	 */
	public void setLocale( ULocale uLocale )
	{
		log.log( Level.FINE, "EngineTask.setLocale: uLocale={0}",
				uLocale == null ? null : uLocale.getDisplayName( ) );
		doSetLocale( uLocale.toLocale( ) );