Currently, If an area with type:single has inherited components, users can add one more component to this area using the "Add component" button on the action bar.

Actual behavior:
A placeholder without add button on the right exist, although users cannot add components by clicking on this place holder, the can add a new components using the "Add component" button on the action bar.

Expected behavior:
The place holder should not appear and the the "Add component" button on the action bar is disabled.

Notes:

This demo project may be useful for this bug: https://git.magnolia-cms.com/projects/DOCUMENTATION/repos/component-inheritance-examples/browse