how to enable "preview app as" function under the app emulator

[rpoonawala]

what settings I need to enable the field below the emulator to view an app from the perspective of the user whose email address is entered into this field. Currently I am unable to navigate to the preview app as shown in the image below

[diogolupcosta · Accepted solution]

This field has the function of showing the creator or co author the 'show ifs' functionalities under USEREMAIL() or USERROLE() premisses built.

[rpoonawala]

Thanks for your prompt response