/**
  * Returns a tooltip showing the distribution of priorities for this container.
  *
  * @return a tooltip showing the distribution of priorities
  */
 public String getToolTip() {
   StringBuilder message = new StringBuilder();
   String separator = " - ";
   for (Priority priority : Priority.values()) {
     if (hasAnnotations(priority)) {
       message.append(priority.getLocalizedString());
       message.append(":");
       message.append(getNumberOfAnnotations(priority));
       message.append(separator);
     }
   }
   return StringUtils.removeEnd(message.toString(), separator);
 }