this.okButton.setEnabled( false );
getOkButton( ).setEnabled( false );
	private void populateList( )	{		try		{			this.okButton.setEnabled( false );			selectValueList.removeAll( );			viewerValueList.clear();			if ( modelValueList != null && modelValueList.size( ) > 0 )			{				Iterator iter = modelValueList.iterator();				while( iter.hasNext()){				Object candiateValue = iter.next();				if ( candiateValue != null )				{					String displayCandiateValue;					if ( candiateValue instanceof Date )						displayCandiateValue = ParameterValidationUtil.getDisplayValue( DesignChoiceConstants.PARAM_TYPE_DATETIME,								null,								candiateValue );					else						displayCandiateValue = DataTypeUtil.toString( candiateValue );					viewerValueList.add( displayCandiateValue );					selectValueList.add( displayCandiateValue );				}}			}			else			{				selectValueList.removeAll( );				modelValueList.clear();				viewerValueList.clear();				ExceptionHandler.openErrorMessageBox( Messages.getString( "SelectValueDialog.errorRetrievinglist" ), Messages.getString( "SelectValueDialog.noExpressionSet" ) ); //$NON-NLS-1$ //$NON-NLS-2$			}			if ( selectValueList.getItemCount( ) > 0 )			{				selectValueList.select( 0 );				this.okButton.setEnabled( true );			}		}		catch ( Exception e )		{			ExceptionHandler.handle( e );		}	}