implement ketcher in jupyter nodebooks

I am trying to implement ketcher in a jupyter notebook. Sadly I am running into

`Blocking request with no referer`

When I try to diplay the ketcher.html. The file opens fine when opened directly in the browser, but is blocked for some reason when displayed in the jupyter nodebook.

it is set in jupyter notebook to block cross-site inclusion (XSSI).

https://github.com/jupyter/notebook/blob/6174498ab0c4047aaed81a1bb5aa71b1fd8c842b/notebook/base/handlers.py#L422

Can you help on where the header is not properly set?

Regards