Bug 201236 Issue about Allow multiple and duplicate values in Layout preview[0705]
Description: Issue about Allow multiple and duplicate values in Layout preview Build number:2.2.1.v20070827 Steps to reproduce: 1. New sample data source and dataset from CUSTOMERS. 2. New a parameter p1, listbox, dynamic, value field COUNTRY, tick on allow duplicate value, tick on allow multiple values. 3. Insert a data item to Layout, set expression as var values=""; for (i=0;i<params["p1"].value.length;i++) values=values+params["p1"].value[i]+"."; values; 4. In Layout, click Preview and select France. Expected result: Display one France. Actual result: Display several France. I tried the same action but preview in Web viewer and extenal html, the result is only one France. Error log:n/a
viewer/org.eclipse.birt.report.viewer/birt/WEB-INF/classes/org/eclipse/birt/report/taglib/ParamDefTag.java
* display text string
	 */
	private String displayTextString;
	/**
	 * parameter group object name
	 */
	private String groupObjName;
	/**
	 * Whether imported js/style files
	 */
	private static final String IMPORT_FILES_ATTR = "IMPORT_FILES_FLAG"; 
	/**
	 * Initialize pageContext
	 * 
	 * @see javax.servlet.jsp.tagext.TagSupport#setPageContext(javax.servlet.jsp.PageContext)
	 */
	public void setPageContext( PageContext context )
	{
		super.setPageContext( context );
		param = new ParamDefField( );
	}
	/**
	 * When reach the end tag, fire this operation
	 * 
	 * @see javax.servlet.jsp.tagext.BodyTagSupport#doEndTag()
	 */
	public int doEndTag( ) throws JspException
	{
		try
		{