Forward port #8209

Closes gh-8210

jupyter_qtconsole/console/frontend_widget.py

@@ -351,7 +351,7 b' class FrontendWidget(HistoryConsoleWidget, BaseFrontendMixin):'
     #---------------------------------------------------------------------------
     def _handle_clear_output(self, msg):
         """Handle clear output messages."""
-        if include_output(msg):
+        if self.include_output(msg):
             wait = msg['content'].get('wait', True)
             if wait:
                 self._pending_clearoutput = True