It might be a good idea to add a zIndex attribute for the CKEditor plugin - as currently it appears lower than the window when 'maximise' is used.

    Drupal.nrembrowser.$dialog = $('<div id="nrembrowser-dialog"></div>')
      .dialog({
        autoopen: false,
        modal: true,
        width: 642,
        height: 'auto',
        title: 'Add media',
		zIndex: '99999'
      })