code: public void addNewSimpleCustomTag(String tagName, String header, String locations) {
          if (tagName == null || locations == null) {
              return;
          }
          Taglet tag = customTags.get(tagName);
          locations = StringUtils.toLowerCase(locations);
          if (tag == null || header != null) {
              customTags.remove(tagName);
              customTags.put(tagName, new SimpleTaglet(tagName, header, locations));
              if (locations != null && locations.indexOf('x') == -1) {
                  checkTagName(tagName);
              }
          } else {
              //Move to back
              customTags.remove(tagName);
              customTags.put(tagName, tag);
          }
      }
docs: Add a new <code>SimpleTaglet</code>.  If this tag already exists
  and the header passed as an argument is null, move tag to the back of the
  list. If this tag already exists and the header passed as an argument is
  not null, overwrite previous tag with new one.  Otherwise, add new
  SimpleTaglet to list.
  @param tagName the name of this tag
  @param header the header to output.
  @param locations the possible locations that this tag
  can appear in.