public void loadOverlays(List<MantleXulOverlay> overlays) {
   for (MantleXulOverlay overlay : overlays) {
     overlayMap.put(overlay.getId(), overlay);
     if (overlay.getId().startsWith("startup")) {
       AsyncXulLoader.loadOverlayFromSource(
           overlay.getSource(), overlay.getResourceBundleUri(), container, this);
     }
   }
 }
 public void removeOverlay(String id) {
   if (overlayMap != null && !overlayMap.isEmpty()) {
     if (overlayMap.containsKey(id)) {
       MantleXulOverlay overlay = overlayMap.get(id);
       AsyncXulLoader.removeOverlayFromSource(
           overlay.getOverlayXml(), overlay.getResourceBundleUri(), container, this);
     } else {
       // Should I log this or throw an exception here
     }
   }
 }