When editing a template part in isolation the Areas UI is surfacing general template parts

[jameskoster]

Description

In my Footer template part I have a general template part for copyright details:

As you can see in the screenshot, both in the template details popover and the Inspector, there's an empty button representing this nested template part.

This raises a question – do we want to surface general template parts in the Areas UI?

We do not currently do this when editing a parent template. So for now it may be simplest to do that same when editing template parts in isolation.

Step-by-step reproduction instructions

1. Add a general template part inside a header or footer template part
2. Edit that header or footer template part in isolation
3. Observe the empty button in the "Areas" UI that represents the general template part

[jameskoster]

Related:

If you edit a template that includes no header or footer template part areas, you also see the strange blank buttons.