import javafx.application.Application;
import javafx.application.Platform;
import javafx.event.ActionEvent;
import javafx.event.EventHandler;
import javafx.scene.*;
import javafx.scene.control.*;
import javafx.scene.layout.*;
import javafx.stage.Stage;

public class CSSBackgroundRenderingBug extends Application {
  public static void main(String[] args) { launch(args); }
  @Override public void start(Stage primaryStage) {
    final EventHandler<ActionEvent> EXIT_HANDLER = new EventHandler<ActionEvent>() {
      @Override public void handle(ActionEvent event) {
        Platform.exit();
      }
    };  
    
    HBox layout = new HBox(10);
    layout.getChildren().addAll(
      closeButton(EXIT_HANDLER),
      closeButton(EXIT_HANDLER),
      closeButton(EXIT_HANDLER)
    );
    
    layout.getStylesheets().add(this.getClass().getResource("roundbutton.css").toExternalForm());
    primaryStage.setScene(new Scene(layout));
    primaryStage.show();
  }

  private Node closeButton(EventHandler<ActionEvent> actionHandler) {
    Button button = new Button();
    button.getStyleClass().add("closebutton");
    button.setOnAction(actionHandler);

    button.setMinSize(StackPane.USE_PREF_SIZE, StackPane.USE_PREF_SIZE);
    button.setPrefSize(30, 30);
    return button;
  }
}