				title: 'Toggle overview (O)',
				icon: '<i class="fa fa-th"></i>',
				action: 'Reveal.toggleOverview();'
				},
				{ icon: '<i class="fa fa-pen-square"></i>',
				title: 'Toggle chalkboard (B)',
				action: 'RevealChalkboard.toggleChalkboard();'
				},
				{ icon: '<i class="fa fa-pen"></i>',
				title: 'Toggle notes canvas (C)',
				action: 'RevealChalkboard.toggleNotesCanvas();'
				},
			]
		},
		menu: {
			loadIcons: false
		}
      };

      // options from URL query string
      var queryOption