In the site editor, it is not possible to edit dynamic content pulled into Query blocks. You can move the blocks around, but not edit their contents. However, you can edit dynamic content for pages (for example if you have a static home page). The same is true in the template editor – you can edit template and content simultaneously.

This can lead to confusing experiences where users struggle to tell where the template ends and the page content begins.

It would be good to try making things consistent here, that is to say: make all dynamic content un-editable when the template is the focus.