public final Image addDecoration(
     IPapyrusDecoration pDecoration, int percentageFromSource, int margin, boolean isVolatile) {
   // use image registry, see bug 401056
   Image image = Activator.getPluginIconImage(Activator.ID, pDecoration.getDecorationImageForGE());
   IDecoration decoration =
       createDecorationImage(decoratorTarget, image, percentageFromSource, margin, isVolatile);
   if (decoration != null) {
     decorations.add(decoration);
     String message = pDecoration.getMessage();
     Label toolTip = getToolTip(message);
     if (decoration instanceof Decoration) {
       ((Decoration) decoration).setToolTip(toolTip);
     }
     return image;
   } else {
     return null;
   }
 }