The post and page editors default to an "abstracted view", where a title block is added, and everything from the Single template except the Content block is stripped out. Currently the way you toggle between show template and abstracted view, is here, in Template > Show template:

This is a valuable tool to switch between the views, yet it is very hidden there. By elevating this control to live in the view dropdown, and persisting on a refresh, it would give more prominence to the option. Mockup:

Note as well in the above mockup, there's an added "template type" icon in the document title interface. This used to be present towards the center near the title. Here it is added back, as a small indicator to help surface the differential in editing visualization. No icon: abstracted. Template template type, full preview.