Flag for use of fixtures is not set

What causes this issue?

The indicator for the use of fixtures is not set.

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?

If layout objects such as layout modules or layout module versions are
already being used in productive operation, execute the conversion
report RWRF_LMVF_USE (transaction WLMVC) before you use fixtures.
Otherwise, the system automatically sets the indicator when the first
fixture is created.

Procedure for System Administrators

Error message extract from SAP system. Copyright SAP SE.