Execute this action by using /SE24 -> Methods (in enhancement mode)

What causes this issue?

The parameter maintenance of a method added as enhancement to a class
cannot be performed on the popup.

System Response

The action is canceled.

How to fix this error?

The parameter administration has to be executed in the form based class
builder, after the class was toggled in enhancement mode (selecting the
relevant enhancement implementation) and you go on method tab.
On this tab you can press the button 'Parameters' or 'Exceptions' in
order to maintain the parameters of the method.

Procedure for System Administrators

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

Error message extract from SAP system. Copyright SAP SE.