FULL PRODUCT VERSION :


A DESCRIPTION OF THE PROBLEM :
If you change the content in current Tab
(add / resize Node)

The TabPane dont render this content or update its size
onle select oter tab and go triggerst the layout change


STEPS TO FOLLOW TO REPRODUCE THE PROBLEM :
run the test programm
add Tabs
add Content to tab
-> switch to second tab and layout is updated


REPRODUCIBILITY :
This bug can be reproduced always.

---------- BEGIN SOURCE ----------
package TabPaneLayout;

import static TabPaneLayout.TabPaneLayoutMaxMain.USE_COMPUTED_SIZE;
import static TabPaneLayout.TabPaneLayoutMaxMain.USE_PREF_SIZE;

import javafx.application.Application;
import javafx.beans.value.ChangeListener;
import javafx.beans.value.ObservableValue;
import javafx.geometry.Pos;
import javafx.scene.Node;
import javafx.scene.Scene;
import javafx.scene.control.Button;
import javafx.scene.control.Label;
import javafx.scene.control.ScrollPane;
import javafx.scene.control.Tab;
import javafx.scene.control.TabPane;
import javafx.scene.layout.BorderPane;
import javafx.scene.layout.ColumnConstraints;
import javafx.scene.layout.GridPane;
import javafx.scene.layout.RowConstraints;
import javafx.scene.layout.VBox;
import javafx.stage.Stage;

/**
 * @author sst
 */
public class TabPaneLayoutMain extends Application {
    /**
     * @param args
     */
    public static void main(String[] args) {
        launch(TabPaneLayoutMain.class, args);
    }

    @Override
    public void start(final Stage stage) throws Exception {
        final BorderPane root = new BorderPane();

        final TabPane tabs = new TabPane();
        tabs.minWidthProperty().addListener(new Change("minWidthProperty"));
        tabs.minHeightProperty().addListener(new Change("minHeightProperty"));
        tabs.prefWidthProperty().addListener(new Change("prefWidthProperty"));
        tabs.prefHeightProperty().addListener(new Change("prefHeightProperty"));
        tabs.maxWidthProperty().addListener(new Change("maxWidthProperty"));
        tabs.maxHeightProperty().addListener(new Change("maxHeightProperty"));
        tabs.widthProperty().addListener(new Change("widthProperty"));
        tabs.heightProperty().addListener(new Change("heightProperty"));

        final Button add = new Button("add");
        root.setTop(add);
        add.setOnAction((event) -> tabs.getTabs().add(new AddTab()));

        final ScrollPane pane = new ScrollPane();
        pane.setContent(tabs);
        root.setCenter(pane);

        stage.setScene(new Scene(root, 400, 400));
        stage.show();
    }

    private void tabPane(final TabPane tabs) {
        for (int tab = 0; tab < 2; tab++) {
            final BorderPane root = new BorderPane();

            final VBox box = new VBox(4);

            BorderPane.setAlignment(box, Pos.TOP_LEFT);
            root.setCenter(box);

            final Tab t = new Tab(String.valueOf(tab));
            t.setContent(root);
            tabs.getTabs().add(t);
        }
    }

    private static final void changeTabPaneSize(final TabPane tabPane) {
        final int index = tabPane.getSelectionModel().getSelectedIndex();
        if (index < 0 || tabPane.getTabs().isEmpty()) {
            return;
        }

        if (tabPane.getTabs().size() == 1) {
            final Tab tab = tabPane.getTabs().remove(0);
            tabPane.getTabs().add(tab);
        } else if (tabPane.getTabs().size() > 1 && index == 0) {
            tabPane.getSelectionModel().select(1);
        } else if (tabPane.getTabs().size() > 1 && index != 0) {
            tabPane.getSelectionModel().select(1);
        }

        tabPane.getSelectionModel().select(index);
    }

    private final class AddTab extends Tab {
        private final int[] row;
        private final GridPane grid;

        private AddTab() {
            super(String.valueOf(System.currentTimeMillis()));

            this.row = new int[]{0};

            this.grid = new GridPane();
            this.grid.setMinSize(USE_PREF_SIZE, USE_PREF_SIZE);
            this.grid.setPrefSize(USE_COMPUTED_SIZE, USE_COMPUTED_SIZE);
            this.grid.setMaxSize(USE_PREF_SIZE, USE_PREF_SIZE);

            this.grid.getColumnConstraints().add(new ColumnConstraints(USE_PREF_SIZE, USE_COMPUTED_SIZE, USE_PREF_SIZE));

            final Button add = new Button("add");
            add.setOnAction((event) -> add(new Label("label")));
            add(add);

            setContent(this.grid);
        }

        private final void add(final Node node) {
            GridPane.setConstraints(node, 0, this.row[0]++);
            this.grid.getChildren().add(node);
            this.grid.getRowConstraints().add(new RowConstraints(USE_PREF_SIZE, USE_COMPUTED_SIZE, USE_PREF_SIZE));

            if (getTabPane() != null) {
                // changeTabPaneSize(getTabPane());
            }
        }
    }

    private final class Change implements ChangeListener<Number> {
        private final String property;

        /**
         * @param property
         */
        private Change(String property) {
            super();
            this.property = property;
        }

        @Override
        public void changed(final ObservableValue<? extends Number> ov, final Number from, Number to) {
            System.out.println(String.format("%s: [%s] -> [%s]", this.property, from, to));
        }
    }
}
---------- END SOURCE ----------

CUSTOMER SUBMITTED WORKAROUND :
- select other tab and go back
- remove + add the tab (only one tab is pressent)

    private static final void changeTabPaneSize(final TabPane tabPane) {
        final int index = tabPane.getSelectionModel().getSelectedIndex();
        if (index < 0 || tabPane.getTabs().isEmpty()) {
            return;
        }

        if (tabPane.getTabs().size() == 1) {
            final Tab tab = tabPane.getTabs().remove(0);
            tabPane.getTabs().add(tab);
        } else if (tabPane.getTabs().size() > 1 && index == 0) {
            tabPane.getSelectionModel().select(1);
        } else if (tabPane.getTabs().size() > 1 && index != 0) {
            tabPane.getSelectionModel().select(1);
        }

        tabPane.getSelectionModel().select(index);
    }