Preview panel not available - no icon to click on (the eye)

How can I enable the preview when editing a page/blog/…
The eye-icon is not showing up. Do I need to enable something?

Its my first time I use Hugo and netlify and I am really amazed !
I’ve set up a ultra minimalistic Hugo webpage, just for testing : https://apo02.netlify.com/

The preview (eye icon) is showing up when using the standard template from netlify.

Thank you !

Found it… option “preview:true” is not working. Had to remove that line:

editor:
  preview: true

Only if you do not want it you have to add option “false”.