Bug 147852 [regression]Combo/listbox parameter doesn't work when put in parameter group
Description: Combo/listbox parameter doesn't work when put in parameter group Steps to reproduce: 1. New a prameter group 2. Insert a textbox parameter 3. Insert a combo/listbox parameter, input several values 4. Preview and select parameter values Expected result: Values can be selected Actual result: Once you selected a value from combo/listbox parameter list, the list would become empty.
viewer/org.eclipse.birt.report.viewer/birt/WEB-INF/classes/org/eclipse/birt/report/context/ScalarParameterBean.java
*/
	private ParameterDefinition parameter = null;
	
	/**
	 * Is parameter value required. 
	 */
	private boolean isRequired = false;
	
	/**
	 * Current parameter value.
	 */
	private String value = null;
	
	/**
	 * Selection lable list. Label is HTML encoded.
	 */
	private Vector selectionList = new Vector( );
	
	/**
	 * selection lable to value mapping. Label is HTML encoded.
	 */
	private Hashtable selectionTable = new Hashtable( );
	
	/**
	 * Whether current value is in the selection list.
	 */
	private boolean valueInList = true;
	/**
	 * Current parameter default value.
	 */