How do I save and exit out of theme

I am testing scribe. I change the homepage, click on save but when I go to leave I am told I will lose all my changes. If I click on the upfront button on the top left I get told I will lose my changes if I leave the page (and I do).
So how am I meant to save my work. Is there something I am missing because just clicking save doesn't do it. I am told my work is being saved and that it has saved but still when I go to exit I am told I can't.

Thanks for your help