No master program specified for the user exits

What causes this issue?

Your view cluster contains events, but you have not specified a master
program in which the form routines which are to be called at the event
are defined.

System Response

The view cluster was not activated.

How to fix this error?

Enter the program names when the 'Events' are defined. The program name
can be defined using the pushbutton 'Change' in the program name output
field.

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

Note:
You must create your form routines in a program of type 'M' (module
pool), 'S' (subroutine pool), or '1' (online program). You cannot define
your form routines in a function group (type 'F'), since the access
mechanism performed on the global data in view cluster maintenance is
not supported in this case.
Include the INCLUDE statement INCLUDE LSVCMCOD in your program to have
access to the global data in view cluster maintenance.

Error message extract from SAP system. Copyright SAP SE.