docs: def _on_dirty_changed(self, dirty):
          """
          Adds a star in front of a dirtt tab and emits dirty_changed.
          """
          widget = self.sender()
          if isinstance(widget, DraggableTabBar):
              return
          parent = widget.parent_tab_widget
          index = parent.indexOf(widget)
          title = parent.tabText(index)
          title = title.replace('* ', '')
          if dirty:
              parent.setTabText(index, "* " + title)
          else:
              parent.setTabText(index, title)
          parent.dirty_changed.emit(dirty)