           # Display the label map (overlay) controls.
           labelmapCtls = gui.addFolder('Overlay')
           labelmapTypeCtl = labelmapCtls.add(_loader, 'Type', labelmapTypes).name('Type')
-          labelmapOpacityCtl = labelmapCtls.add(volume.labelmap, 'opacity', 0, 1)
+          labelmapOpacityCtl = labelmapCtls.add(volume.labelmap, 'opacity', 0, 1).name('Opacity')
           labelmapCtls.open()
 
           # Change the label map type callback.

              volume.labelmap.visible = true
            else
              volume.labelmap.visible = false
            return

        # Adjust the camera position.
        renderer.camera.position = [0, 0, 240]

      open: (element) ->

        # The available label map types.
        labelmapTypes = []
        labelmapTypes.push overlay.label for overlay in overlays

        # The XTK renderer for this image.
        renderer = new X.renderer3D()
