Run following test program. Text of button is cut off. Removing the setMinSize on the label restores correct functionality.

import javafx.application.Application;
import javafx.scene.Scene;
import javafx.scene.control.Button;
import javafx.scene.control.Label;
import javafx.scene.layout.BorderPane;
import javafx.stage.Stage;

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

public void start(Stage stage) throws Exception {
Label l = new Label("1");
l.setMinSize(20, 20);
Button b = new Button("Button", l);
BorderPane bp = new BorderPane(b);
Scene scene = new Scene(bp, 800, 600);
stage.setScene(scene);
stage.show();
}
}