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
if ( !isStatic( )
					&& columnChooser != null
					&& columnChooser.getItemCount( ) == 0 )
			{
				errorMessage = ERROR_MSG_NO_AVAILABLE_COLUMN;
			}
			else if ( defaultValue == null
					&& ( PARAM_CONTROL_COMBO.equals( getSelectedControlType( ) ) || DesignChoiceConstants.PARAM_CONTROL_RADIO_BUTTON.equals( getSelectedControlType( ) ) ) )
			{
				
				if ( !canBeNull( ) || !containValue( null, null, COLUMN_VALUE ) )
				{
					
					
					errorMessage = ERROR_MSG_NO_DEFAULT_VALUE;
				}
			}
		}
		if ( errorMessage != null )
		{
			errorMessageLine.setText( errorMessage );
			errorMessageLine.setImage( ERROR_ICON );
		}
		else
		{
			errorMessageLine.setText( "" ); 
			errorMessageLine.setImage( null );
		}
		if ( promptMessageLine != null && !promptMessageLine.isDisposed( ) )
		{