Compile and run this sample:

package tabpaneclosingvisualartefacts;

import javafx.application.Application;
import javafx.event.ActionEvent;
import javafx.event.EventHandler;
import javafx.scene.Scene;
import javafx.scene.control.Button;
import javafx.scene.control.Tab;
import javafx.scene.control.TabPane;
import javafx.scene.layout.StackPane;
import javafx.stage.Stage;

public class TabPaneClosingVisualArtefacts extends Application {
    
    @Override
    public void start(Stage primaryStage) {
        TabPane pane = new TabPane();
        final Tab tab1 = new Tab("Tab1");
        pane.getTabs().addAll(tab1, new Tab("Tab2"), new Tab("Tab3"), new Tab("Tab4"), new Tab("Tab5"));

        Scene scene = new Scene(pane,200,200);
        primaryStage.setScene(scene);
        primaryStage.show();
    }

    /**
     * @param args the command line arguments
     */
    public static void main(String[] args) {
        launch(args);
    }
    
}

Result: Switcher for Tab Panes in TabPane header is incorrect rendered.

Now move mouse cursor over tab pane switcher - now is correct rendered.

See screenshots:
1. http://i62.tinypic.com/f0da48.png (before move mouse cursor over tab pane switcher)
2. http://i61.tinypic.com/kczcib.png (after move mouse cursor over tab pane switcher)