Ionic themeablebrowser buttons not working

Hi, my themeable browser menu not appearing.

Please see below screenshot

 const options: ThemeableBrowserOptions = {
      statusbar: {
          color: '#ffffffff'
      },
      toolbar: {
          height: 44,
          color: '#f0f0f0ff'
      },
      title: {
          color: '#003264ff',
          showPageTitle: true
      },
      backButton: {
          image: 'back',
          imagePressed: 'back_pressed',
          align: 'left',
          event: 'backPressed'
      },
      forwardButton: {
          image: 'forward',
          imagePressed: 'forward_pressed',
          align: 'left',
          event: 'forwardPressed'
      },
      closeButton: {
          image: 'close',
          imagePressed: 'close_pressed',
          align: 'left',
          event: 'closePressed'
      },
      customButtons: [
          {
              image: 'share',
              imagePressed: 'share_pressed',
              align: 'right',
              event: 'sharePressed'
          }
      ],
      menu: {
          image: 'menu',
          imagePressed: 'menu_pressed',
          title: 'Test',
          cancel: 'Cancel',
          align: 'right',
          items: [
              {
                  event: 'helloPressed',
                  label: 'Hello World!'
              },
              {
                  event: 'testPressed',
                  label: 'Test!'
              }
          ]
      },
      backButtonCanClose: true
  };
  const browser: ThemeableBrowserObject = this.themeableBrowser.create('https://ionic.io', '_blank', options);