anchorPane.setOnKeyPressed(new EventHandler<KeyEvent>() {
        @Override
        public void handle(KeyEvent event) {
            if (event.getCode() == KeyCode.getKeyCode("F4")) {
                Tab tab = new Tab("Tab " + (tabPane.getTabs().size() + 1));

                try {
                    Parent table = FXMLLoader.load(getClass().getResource("/sample/ui/seller/saleListTable.fxml"));
                    StackPane stackPane = new StackPane();
                    stackPane.getChildren().add(table);
                    tab.setContent(stackPane);

                } catch (IOException e) {
                    e.printStackTrace();
                }

                tabPane.getTabs().add(tab);
                tabPane.getSelectionModel().selectLast();
            }
        }
    });

AnchorPane.setTopAnchor(table,0.0); 
AnchorPane.setRightAnchor(table,0.0); 
AnchorPane.setBottomAnchor(table,0.0); 
AnchorPane.setLeftAnchor(table,0.0);