The deletion of assignments to layout module variants is not allowed

What causes this issue?

You wanted to delete the assignment of the material to a layout module
variant. This is not allowed when materials are maintained in dialog
mode.

System Response

The system issues an error message and will not allow you to continue with this transaction until the error is resolved.

How to fix this error?

Procedure for System Administrators

Error message extract from SAP system. Copyright SAP SE.