When using the HTMLEditor component, pressing Tab creates a tab in the text, but makes the cursor disappear. You can still keep typing at the correct position, but the cursor only reappears when you press Tab again.

Used code to reproduce:

import javafx.application.Application;
import javafx.scene.Scene;
import javafx.scene.layout.VBox;
import javafx.scene.web.HTMLEditor;
import javafx.stage.Stage;

public class EditorTest extends Application {

    public static void main(String[] args) {
        launch(args);
    }
    
    public void start(Stage primaryStage) {
     VBox root = new VBox();
     HTMLEditor editor = new HTMLEditor();
    
     root.getChildren().add(editor);
     primaryStage.setScene(new Scene(root));
     primaryStage.show();
    }
}