Hi there @stepis !
Don here from Shopify. 
You might be referring to the online store preview mode, accessed whenever you click on the ‘view’ icon in your admin; such as beside the Online store sales channel or at the top of product pages in your admin.
This would allow you to see a preview of your storefront where you should still be able to see the black edit bar you refer to for editing your homepage, collection pages or product pages.
Check it out and see if you can still access that in this way!
Regards,
Don