Editor vs. Viewer mode with Hidden Objects

A way to differentiate between what the editor (Game Master) can see and what the viewer can see (Player). Can be seen as a similar feature as 'present mode' in apps such as Powerpoint or Google Slides.

Alongside this then, the ability to decide what aspects are and are not viewable in Viewer mode, such as hidden enemies that the editor can see, but the viewers can't (yet).