Tab content is empty when tab is dragged

Question

I have two TabPanes which can move tabs each other. This is the code of the TabPane which receives the dragged tabs from the user:
tabPane.setOnDragDropped(new EventHandler<DragEvent>()
            @Override
            public void handle(DragEvent event)
                final Dragboard dragboard = event.getDragboard();
                if (dragboard.hasString()
                        && TAB_DRAG_KEY.equals(dragboard.getString())
                        && DragBuffer.getDraggingTab().get() != null
                        && DragBuffer.getDraggingTab().get().getTabPane() != tabPane)
                    final Tab tab = DragBuffer.getDraggingTab().get();
                    tab.getTabPane().getTabs().remove(tab);
                    tabPane.getTabs().add(tab);
                    tabPane.getSelectionModel().select(tab);
                    event.setDropCompleted(true);
                    DragBuffer.getDraggingTab().set(null);
                    event.consume();
I noticed that when I drag the tab into the target TabPane the content of the tab is empty. But when I swith to the next tab of the target tabPane and return back I can see the content. This is couced by this line:
tab.getTabPane().getTabs().remove(tab);
Can you tell me how I can change the logic in order to prevent the empty tab body?
Ref javafx 2 - Tab content is empty when tab is dragged - Stack Overflow

Answer 1

This looks like a bug; I see the same thing in the context of your other thread. I can't seem to find a workaround. I have some sample code below which demonstrates the same problem without cluttering the code with drag and drop. This should move the selected tab in the bottom tapPane to the top tabPane ("Up" button) or the selected tab in the top tabPane to the bottom tabPane ("Down" button). When a tab is moved it is automatically selected; moving a tab to the top tabPane fails to show its content. (Strangely, moving a tab to the bottom tabPane works fine.) You should probably file a JIRA; reference this thread ("discussion" in the new forum-speak).
import java.util.Random;
import javafx.application.Application;
import javafx.beans.binding.Bindings;
import javafx.event.ActionEvent;
import javafx.event.EventHandler;
import javafx.scene.Scene;
import javafx.scene.control.Button;
import javafx.scene.control.Label;
import javafx.scene.control.Tab;
import javafx.scene.control.TabPane;
import javafx.scene.layout.HBox;
import javafx.scene.layout.Pane;
import javafx.scene.layout.VBox;
import javafx.stage.Stage;
public class TabSelectionTest extends Application {
@Override
  public void start(Stage primaryStage) {
  final TabPane tabPane1 = new TabPane();
  final Random rng = new Random();
  final int NUM_TABS = 4 ;
  for (int i=1; i<=NUM_TABS; i++) {
    tabPane1.getTabs().add(createTab(rng, i));
  final TabPane tabPane2 = new TabPane();
    for (int i=1; i<=NUM_TABS; i++) {
      tabPane2.getTabs().add(createTab(rng, i+NUM_TABS));
  final Button moveToPane1Button = new Button("Up");
  final Button moveToPane2Button= new Button("Down");
  final HBox buttons = new HBox(10);
  buttons.getChildren().addAll(moveToPane1Button, moveToPane2Button);
  moveToPane1Button.setOnAction(new EventHandler<ActionEvent>() {
      @Override
      public void handle(ActionEvent event) {
        Tab selectedTab = tabPane2.getSelectionModel().getSelectedItem();
        tabPane2.getTabs().remove(selectedTab);
        tabPane1.getTabs().add(selectedTab);
        tabPane1.getSelectionModel().select(selectedTab);
    moveToPane2Button.setOnAction(new EventHandler<ActionEvent>() {
      @Override
      public void handle(ActionEvent event) {
        Tab selectedTab = tabPane1.getSelectionModel().getSelectedItem();
        tabPane1.getTabs().remove(selectedTab);
        tabPane2.getTabs().add(selectedTab);
        tabPane2.getSelectionModel().select(selectedTab);
    moveToPane1Button.disableProperty().bind(Bindings.isEmpty(tabPane2.getTabs()));
    moveToPane2Button.disableProperty().bind(Bindings.isEmpty(tabPane1.getTabs()));
    VBox root = new VBox(10);
  root.getChildren().addAll(tabPane1, buttons, tabPane2);
  primaryStage.setScene(new Scene(root, 600, 500));
  primaryStage.show();
  private Tab createTab(Random rng, int i) {
    Tab tab = new Tab("Tab "+i);
    Pane pane = new Pane();
    pane.setMinSize(600, 400);
    String style = String.format("-fx-background-color: rgb(%d,  %d, %d);", rng.nextInt(256), rng.nextInt(256), rng.nextInt(256));
    pane.setStyle(style);
    pane.getChildren().add(new Label("This is tab "+i));
    tab.setContent(pane);
    return tab ;
  public static void main(String[] args) {
  launch(args);