code: def get_stack_index(self, stack_index, plugin_index):
          
          other_plugins_count = sum([other_tabs[0].count() \
                                     for other_tabs in \
                                     self.plugins_tabs[:plugin_index]])
          real_index = stack_index - other_plugins_count
  
          return real_index
docs: Get the real index of the selected item.