Bug 144106 [Regression]Parameter request page pops up twice while running the report with cascading parameter
Steps to reproduce: 1.Add a cascading parameter group with a parameter 2.Preview Expected result: The parameter request page just pops up once for input value Actual result: The parameter request page pops up twice when inputting parameter value
viewer/org.eclipse.birt.report.viewer/birt/WEB-INF/classes/org/eclipse/birt/report/context/ViewerAttributeBean.java
Collection parameterDefList = this.getReportService( )
				.getParameterDefinitions( reportDesignHandle, options, false );
		
		this.missingParameter = validateParameters( parameterDefList,
				this.parametersAsString );
	}
	/**
	 * parse paramenters from config file.
	 * 
	 * @param request
	 *            HttpServletRequest
	 * @return
	 */
	protected void parseConfigVars( HttpServletRequest request,
			Collection parameterList )
	{
		assert reportDesignHandle != null;
		this.configMap = new HashMap( );
		
		String reportConfigName = ParameterAccessor
				.getConfigFileName( reportDesignName );
		if ( reportConfigName == null )
			return;
		
		SessionHandle sessionHandle = DesignEngine.newSession( ULocale.US );
		ReportDesignHandle handle = null;
		try
		{
			
			handle = sessionHandle.openDesign( reportConfigName );