The dynpro was modified and cannot be deleted

What causes this issue?

This screen has been edited in customer enhancement mode, and contains
enhancements.

System Response

You may not delete screens containing enhancements.

How to fix this error?

If you are sure that you want to delete the screen, you must first
reset it to its original (SAP standard) state. Any enhancements will be
lost.
You can reset the screen by choosing Edit -> Enhancements -> Reset from
the Screen Painter initial screen.

Error message extract from SAP system. Copyright SAP SE.