code: def set_current_widget(self, fig_browser):
          
          self.stack.setCurrentWidget(fig_browser)
          # We update the actions of the options button (cog menu) and
          # we move it to the layout of the current widget.
          self.refresh_actions()
          fig_browser.setup_options_button()
docs: Set the currently visible fig_browser in the stack widget, refresh the
          actions of the cog menu button and move it to the layout of the new
          fig_browser.