Select messages first

What causes this issue?

By double-clicking in the upper window, you can display a message with
all its subordinate messages in the lower window. There, you can use
the selection column to select messages.

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.