Bug 168808 Display text is lost after launching import values dialog
Steps to reproduce: 1.new a parameter; 2.select list box control type; 3.press "Import Values" button to import some values; 4.assign display texts for the imported values; 5.press "Import Values" button to launch import values dialog again; 6.press ok button on dialog; Expected result: The previous assigned display texts are remained. Actual result: The previous display texts are lost.
UI/org.eclipse.birt.report.designer.ui/src/org/eclipse/birt/report/designer/ui/dialogs/ParameterDialog.java
{
			return string;
		}
		try
		{
			String pattern = formatPattern;
			if ( formatPattern == null )
			{
				if ( isCustom( ) )
				{
					return string;
				}
				pattern = formatCategroy;
			}
			if ( DesignChoiceConstants.PARAM_TYPE_DATETIME.equals( getSelectedDataType( ) ) )
			{
				Date date = DataTypeUtil.toDate( string, ULocale.US );
				DateFormatter formatter = new DateFormatter( pattern );
				string = formatter.format( date );
			}
			else if ( DesignChoiceConstants.PARAM_TYPE_FLOAT.equals( getSelectedDataType( ) ) )
			{
				string = new NumberFormatter( pattern ).format( DataTypeUtil.toDouble( string )
						.doubleValue( ) );
			}
			else if ( DesignChoiceConstants.PARAM_TYPE_DECIMAL.equals( getSelectedDataType( ) ) )
			{
				string = new NumberFormatter( pattern ).format( DataTypeUtil.toBigDecimal( string ) );
			}
			else if ( DesignChoiceConstants.PARAM_TYPE_STRING.equals( getSelectedDataType( ) ) )