Window.parent undefined in iframe causes cypress tests to fail

Hello,
It took me some time to realize why cypress could not work with elements inside the theia iframe.
It so happens that, probably for security reasons, parent, top, and frameElement are deleted from the iframe window at https://github.com/eclipse-theia/theia/blob/c4fed0d1c52e3e6dca4c9e8b4738350274d6570b/packages/plugin-ext/src/main/browser/webview/pre/main.js#L177

Could you let me know if there would be some provisioned toggle that I could use to prevent that from happening or am I just left with hacking the code ?

Cheers