import javafx.application.Application;
import javafx.application.Platform;
import javafx.collections.FXCollections;
import javafx.collections.ObservableList;
import javafx.collections.transformation.FilteredList;
import javafx.scene.Scene;
import javafx.scene.control.ComboBox;
import javafx.scene.control.TextField;
import javafx.scene.layout.HBox;
import javafx.stage.Stage;

public class Main extends Application {
    public void start(Stage stage) {
        HBox root = new HBox();

        ComboBox<String> prim = new ComboBox<String>();
        prim.setEditable(true);
        
        ComboBox<String> sec = new ComboBox<String>();
        sec.setEditable(true);

        
        ObservableList<String> itemsPrim = FXCollections.observableArrayList("Ahh", "Bhh", "Chh", "Dhh", "Ehh", "Fhh",
                "Ghh", "Hhh", "Ihh", "Jhh");
        ObservableList<String> itemsSec = FXCollections.observableArrayList("One", "Two", "Three", "Four", "Five", "Six",
                "Seven", "Eight", "Nine", "Ten");

      
        FilteredList<String> filteredItems = new FilteredList<String>(itemsSec, p -> true);

  
        prim.getEditor().textProperty().addListener((obs, oldValue, newValue) -> {
            final TextField editor = prim.getEditor();
            final String selected = prim.getSelectionModel().getSelectedItem();

   
            Platform.runLater(() -> {
            
                if (selected == null || !selected.equals(editor.getText())) {
                    filteredItems.setPredicate(item -> {
                      
                        if (item.toUpperCase().startsWith(newValue.toUpperCase())) {
                            return true;
                        } else {
                            return false;
                        }
                    });
                }
            });
        });

        prim.setItems(filteredItems);
        sec.setItems(itemsPrim);

        root.getChildren().add(prim);
        root.getChildren().add(sec);

        Scene scene = new Scene(root);
        stage.setScene(scene);
        stage.show();
    }

    public static void main(String[] args) {
        launch();
    }
}