При смене сцены fxml - все поля null

public class ScreenController {

    private final HashMap<String, Pane> screenMap = new HashMap<>();
    private final Scene main;

    public ScreenController(Scene main) {
        this.main = main;
    }

    public void addScreen(String name, Pane pane){
        screenMap.put(name, pane);
    }

    protected void removeScreen(String name){
        screenMap.remove(name);
    }

    public void activate(String name){
        main.setRoot( screenMap.get(name) );
    }

    public HashMap<String, Pane> getScreenMap() {
        return screenMap;
    }
}

@Slf4j
public class Controller implements Initializable {
    // *** FXML *** //
    // register
    public TextField firstName;
    public TextField lastName;
    public TextField registerLogin;
    public TextField email;
    public TextField showRegisterPasswordField;
    public PasswordField registerPassword;
    public TextField showRegisterConfirmField;
    public PasswordField registerConfirmField;
    // login
    public Button cancelButton;
    public Button authButton;
    public PasswordField passwordField;
    public TextField loginField;
    // app
    public ListView <String> clientView;
    public ListView <String> serverView;
    public ProgressBar progressBar;
    public Button sendFileButton;
    public Button downloadFileButton;
    public Button openClientDirectoryButton;
    public Button openServerDirectoryButton;
    public Label clientPathLabel;
    public Label serverPathLabel;

    // *** END FXML *** //


    private static final App RUN = new App();
    private static final ClientConfiguration CONFIG = new ClientConfiguration();
    private static final EventHandler EVENT_HANDLER = new EventHandler();
    private ObjectDecoderInputStream in;
    private ObjectEncoderOutputStream out;

    @Override
    public void initialize(URL location, ResourceBundle resources) {
        try {

            Socket socket = new Socket(CONFIG.HOST, CONFIG.PORT);
            out = new ObjectEncoderOutputStream(socket.getOutputStream());
            in = new ObjectDecoderInputStream(socket.getInputStream());

            refreshClientView();

            Thread daemon = new Thread(() -> {
                try {
                    while (true) {
                        Command command = (Command) in.readObject();
                        log.debug("received: {}", command);
                        switch (command.getType()) {
                            case AUTH_RESPONSE:
                                AuthResponseMessage authResponseMessage = (AuthResponseMessage) command;
                                EVENT_HANDLER.handleAuthResponse(authResponseMessage);
                                break;
                            case REGISTER_RESPONSE:
                                RegisterResponseMessage registerResponseMessage = (RegisterResponseMessage) command;
                                EVENT_HANDLER.handleRegisterResponse(registerResponseMessage);
                                break;
                        }
                    }
                } catch (Exception e) {
                    log.error("exception while read from input stream", e);
                }
            });
            daemon.setDaemon(true);
            daemon.start();
        } catch (IOException ioException) {
            log.error("Error: ", ioException);
        }
    }

@SneakyThrows
    public void setPathToClientDir(String rootDir) {
        Platform.runLater(() -> {
            RUN.toggleSceneToApp();
            clientPathLabel.setText(rootDir);
        });

    }

<?xml version="1.0" encoding="UTF-8"?>

<?import javafx.scene.control.Button?>
<?import javafx.scene.control.Label?>
<?import javafx.scene.control.ListView?>
<?import javafx.scene.control.ProgressBar?>
<?import javafx.scene.image.Image?>
<?import javafx.scene.image.ImageView?>
<?import javafx.scene.layout.AnchorPane?>
<?import javafx.scene.text.Font?>

<AnchorPane id="AnchorPane" maxHeight="-Infinity" maxWidth="-Infinity" minHeight="-Infinity" minWidth="-Infinity"
            prefHeight="514.0" prefWidth="573.0" xmlns="http://javafx.com/javafx/8.0.171"
            xmlns:fx="http://javafx.com/fxml/1" fx:controller="handlers.Controller">
    <children>
        <Label layoutX="35.0" layoutY="26.0" text="My Computer" />
        <ListView fx:id="clientView" layoutX="35.0" layoutY="81.0" prefHeight="332.0" prefWidth="229.0" />
        <Label layoutX="312.0" layoutY="26.0" text="Server" />
        <ListView fx:id="serverView" layoutX="312.0" layoutY="81.0" prefHeight="332.0" prefWidth="229.0" />
        <ProgressBar fx:id="progressBar" layoutX="28.0" layoutY="461.0" prefHeight="20.0" prefWidth="512.0"
                     progress="0.0" />
        <Label layoutX="35.0" layoutY="431.0" text="File transfer:" />
        <Button fx:id="sendFileButton" disable="true" layoutX="269.0" layoutY="204.0" mnemonicParsing="false"
                 prefHeight="26.0" prefWidth="19.0">
            <font>
                <Font size="15.0" />
            </font>
            <graphic>
                <ImageView fitHeight="18.0" fitWidth="18.0" pickOnBounds="true" preserveRatio="true">
                    <image>
                        <Image url="images/arrowRight.png" />
                    </image>
                </ImageView>
            </graphic>
        </Button>

        <Button fx:id="downloadFileButton" disable="true" layoutX="269.0" layoutY="243.0" mnemonicParsing="false"
                prefHeight="26.0" prefWidth="19.0">
            <font>
                <Font size="15.0" />
            </font>
            <graphic>
                <ImageView fitHeight="18.0" fitWidth="18.0" pickOnBounds="true" preserveRatio="true">
                    <image>
                        <Image url="images/arrowLeft.png" />
                    </image>
                </ImageView>
            </graphic>
        </Button>
       <Button fx:id="openClientDirectoryButton" layoutX="211.0" layoutY="21.0" mnemonicParsing="false"
               text="Open"/>
       <Button fx:id="openServerDirectoryButton" layoutX="487.0" layoutY="21.0" mnemonicParsing="false"/>
       <Label fx:id="clientPathLabel" layoutX="35.0" layoutY="45.0" text="Path:" />
       <Label fx:id="serverPathLabel" layoutX="312.0" layoutY="45.0" text="Path:" />
    </children>
</AnchorPane>

<?xml version="1.0" encoding="UTF-8"?>

<?import javafx.scene.control.*?>
<?import javafx.scene.layout.*?>

<AnchorPane id="AnchorPane" maxHeight="-Infinity" maxWidth="-Infinity" minHeight="-Infinity" minWidth="-Infinity"
            prefHeight="184.0" prefWidth="203.0" xmlns="http://javafx.com/javafx/8.0.202-ea"
            xmlns:fx="http://javafx.com/fxml" fx:controller="handlers.Controller">
    <children>
        <Button fx:id="cancelButton" layoutX="14.0" layoutY="149.0" mnemonicParsing="false"
                onAction="#clickCancelButton" prefWidth="81.0"
                text="Cancel" />
        <Button fx:id="authButton" layoutX="108.0" layoutY="149.0" mnemonicParsing="false"
                onAction="#sendAuthMessageToServer" prefWidth="81.0"
                text="Login" />
        <Label layoutX="14.0" layoutY="22.0" text="Login:" />
        <PasswordField fx:id="passwordField" layoutX="8.0" layoutY="101.0" prefHeight="26.0" prefWidth="163.0" />
        <TextField fx:id="loginField" layoutX="8.0" layoutY="45.0" prefWidth="187.0" />
        <Label layoutX="14.0" layoutY="81.0" text="Password:" />
        <CheckBox layoutX="177.0" layoutY="105.0" mnemonicParsing="false" />
    </children>
</AnchorPane>