How to use the template for pages

I have a website where all my pages have the same boxed layout. I created a template and set the conditions to PostType > Pages. Where I want the content to appear I placed the Post Content element and set it’s data source to Bricks (so it renders the content from the Bricks builder from that specific page) So far so good.

What is expect to see when editing an individual page is:

(So the page Template is visible on the background, which makes editing a page visually easy)
But what I get is:

Is this a bug or am I missing something? OR should I take a whole different route?
Thanks in advance!