Reproducible: always
Platform-specific: no (reproducible on windows, linux)
Is a regression: yes
Introduced in: 8u60b09, works fine for 8u60b08
Steps to reproduce: run the following sample, or open facebook.com (e.g.) login page in webview.
Expected result: expand button is visible
Actual result: select looks like text input or something like that

import javafx.application.Application;
import javafx.scene.Scene;
import javafx.scene.web.WebView;
import javafx.stage.Stage;

public class SimpleWebView extends Application {

    @Override
    public void start(Stage primaryStage) throws Exception {
        WebView view = new WebView();
        view.setMinWidth(800);
        view.setMinHeight(600);
        view.getEngine().loadContent(
                "<select style='border-radius:0px;'><option>Select with border-radius: 0px</option></select>"
                + "<select style='border-radius:10px;'><option>Select with border-radius: 10px</option></select>"
                + "<select><option>Select without border-radius</option></select>"
        );
        primaryStage.setScene(new Scene(view));
        primaryStage.show();
    }

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