code: def activated(self, item):
          
          editor_item = self.editor_items.get(
              self.editor_ids.get(self.current_editor))
          line = 0
          if item == editor_item:
              line = 1
          elif isinstance(item, TreeItem):
              line = item.line
  
          self.freeze = True
          root_item = self.get_root_item(item)
          if line:
              self.parent().edit_goto.emit(root_item.path, line, item.text(0))
          else:
              self.parent().edit.emit(root_item.path)
          self.freeze = False
  
          parent = self.current_editor.parent()
          for editor_id, i_item in list(self.editor_items.items()):
              if i_item is root_item:
                  for editor, _id in list(self.editor_ids.items()):
                      if _id == editor_id and editor.parent() is parent:
                          self.current_editor = editor
                          break
                  break
docs: Double-click event