* [maixcam2] del vlm after exit

Author: lxowalle

projects/app_vlm/main.py

@@ -261,6 +261,8 @@ def run(self):
             self.show_ui()
         if self.vlm:
             self.vlm.cancel()
+            del self.vlm
+            self.vlm = None
 
 if __name__ == '__main__':
     appication = App()