问JavaFx布局:消失/无组织窗格

EN

BorderPane bp = new BorderPane();
button1 = new Button("Undo");
button2 = new Button("Erase");
HBox hb = new HBox(10);
hb.getChildren().addAll(button1, button2);

TilePane tp = new TilePane();
vb = new VBox();
vb.setPadding(new Insets(10, 10, 10, 10));
vb.setSpacing(25);
vb.setStyle("-fx-padding: 10;" + 
        "-fx-border-style: solid inside;" + 
        "-fx-border-width: 2;" +
        "-fx-border-insets: 5;" + 
        "-fx-border-radius: 5;" + 
        "-fx-border-color: black;");

colorCombo = new ComboBox<String>();
colorCombo.getItems().addAll("Black","Blue","Green","Red","Yellow","Orange","Pink");
colorCombo.setValue("Black");
colorCombo.setMinWidth(100);

ToggleGroup group1 = new ToggleGroup();

rbutton1 = new RadioButton("Rectangle");
rbutton1.setToggleGroup(group1);
rbutton1.setMinWidth(80);
rbutton1.setSelected(true);
rbutton2 = new RadioButton("Circle");
rbutton2.setToggleGroup(group1);
rbutton2.setMinWidth(80);

canvas = new Pane();
canvas.setStyle("-fx-background-color: beige;");

vb.getChildren().addAll(colorCombo, rbutton1, rbutton2);
tp.getChildren().add(vb);
bp.setLeft(tp);
bp.setBottom(hb);
bp.setRight(canvas);
this.getChildren().addAll(bp);