I've found this bug while investigating a leak in the Browser demo. Below is a minimized test. To reproduce, I ran the test under profiler and selected tabs one by one. On each tab I clicked into the text field and typed a few letters into it. Then I closed all tabs except Tab0, and created a heap dump (attached as TextFieldLeak.hprof).

The dump shows five TextField objects (there should be only one), three of them are referenced from QuantumToolkit.animationRunnable. I suppose this may be related to the blinking caret.

import javafx.application.Application;
import javafx.scene.Scene;
import javafx.scene.control.Tab;
import javafx.scene.control.TabPane;
import javafx.scene.control.TextField;
import javafx.stage.Stage;

public class Test extends Application {

    @Override public void start(Stage stage) {
        TabPane tabs = new TabPane();
        for (int i=0; i<5; i++) {
            TextField field = new TextField("Field" + i);
            Tab tab = new Tab("Tab" + i);
            tab.setContent(field);
            tabs.getTabs().add(tab);
        }
        stage.setScene(new Scene(tabs));
        stage.sizeToScene();
        stage.show();
    }

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