code: public ElementBase registerFromId(String path, String id) throws Exception {
          return registerFromId(path, id, null);
      }
docs: Registers the plugin with the specified id and path. If a tree path is absent, the plugin is
  associated with the tab itself.
  
  @param path Format is &lt;tab name&gt;\&lt;tree node path&gt;
  @param id Unique id of plugin
  @return Container created for the plugin.
  @throws Exception Unspecified exception.