See screenshot

The insite editing mode as a button that set EDIT on or off.
When the edit is set to ON, all the interaction on blocks is added on top of the site page. Potentially, we could also decide to disable internal navigation (this is something we should consider later)
When the edit is set to OFF, it is a must that the user can navigate in the iframe / area that preview the site. This means it shall not be just a passive preview but should allow browsing and use of the site itself.