Why is Simulink Variant Manager unable to find the Simulink.VariantControl object that controls the active choice of Simulink.VariantVariable objects?

I'm following through with this documentation example: Change Active Values and Activation Time of Variant Parameters - MATLAB & Simulink (mathworks.com). It uses a Simulink.VariantControl object to select the active choice for multiple Simulink.VariantVariable parameters. However, I would like to interage the selection of variant parameters by:

1. Open the variant manager of this example model:
2. Import control variables across model hierarchy:
3. However, clicking on this button results in error prompt reporting that the Simulink.VariantControl object can't be found:

Is this a bug of Simulink?