How to set tabs position in JavaFX - javafx-2

Question

I have this JavaFX code with tabs. Can you tell me how I can set the position of the tabs panel to be always on the left side of the main stage:
VBox stackedTitledPanes = createStackedTitledPanes();
ScrollPane scroll = makeScrollable(stackedTitledPanes);
TabPane tabPane = new TabPane();
BorderPane mainPane = new BorderPane();
tabPane.setStyle("-fx-font-size: 12pt;"); // Set global size for the font
// Create Tabs
Tab tabA = new Tab();
tabA.setText("Main Component");
tabA.setStyle("-fx-font-size: 12pt;"); // Set size of the tab name
// Add something in Tab
StackPane tabA_stack = new StackPane();
tabA_stack.setAlignment(Pos.CENTER);
tabA_stack.getChildren().add(scroll);
tabA.setContent(tabA_stack);
tabPane.getTabs().add(tabA);
Tab tabB = new Tab();
tabB.setText("Second Component");
tabB.setStyle("-fx-font-size: 12pt;"); // Set size of the tab name
// Add something in Tab
StackPane tabB_stack = new StackPane();
tabB_stack.setAlignment(Pos.CENTER);
tabB_stack.getChildren().add(new Label("Label#Tab B"));
tabB.setContent(tabB_stack);
tabPane.getTabs().add(tabB);
Tab tabC = new Tab();
tabC.setText("Last Component");
tabC.setStyle("-fx-font-size: 12pt;"); // Set size of the tab name
// Add something in Tab
StackPane tabC_vBox = new StackPane();
tabC_vBox.setAlignment(Pos.CENTER);
tabC_vBox.getChildren().add(new Label("Label#Tab C"));
tabC.setContent(tabC_vBox);
tabPane.getTabs().add(tabC);
mainPane.setCenter(tabPane);
mainPane.setPrefSize(395, 580);
mainPane.setLayoutX(850);
mainPane.setLayoutY(32);
scroll.setPrefSize(395, 580);
scroll.setLayoutX(850);
scroll.setLayoutY(32);
root.getChildren().add(mainPane);

Answer 1

Update
Sounds like you want to change your stackedTitledPane from a VBox to a BorderPane.
So this code:
VBox stackedTitledPanes = new VBox();
becomes:
BorderPane stackedTitledPanes = new BorderPane();
Then when you want to add your nodes, you specify which section you want to put them (I put a label in the center pane as a filler):
stackedTitledPanes.setLeft(mainPane);
stackedTitledPanes.setCenter(new Label("Main Content"));
Old answer
This will put the tabs on the left (I'm assuming this is what you're looking for):
tabPane.setSide(Side.LEFT);