Run code below, and note that the 'Hello world!' text is shown even though the button is contained within a disabled tab.

import javafx.application.Application;
import javafx.scene.Scene;
import javafx.scene.control.Button;
import javafx.scene.control.Tab;
import javafx.scene.control.TabPane;
import javafx.stage.Stage;

public class App extends Application {


    @Override
    public void start(Stage stage) {

        TabPane pane = new TabPane();
        final Tab disabled = new Tab("Disabled");
        disabled.setContent(new Button("Hello world!"));
        disabled.setDisable(true);
        pane.getTabs().add(disabled);

        pane.getTabs().addAll(new Tab("ABCABCABCABC"), new Tab("ABC"));

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

    }

    public static void main(String[] args) {
        Application.launch(args);
    }
}