Place the cursor on a &

What causes this issue?

You want to copy an object. This is not possible, because the object
you selected is a class.

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?

Please place the cursor on an object that is not a class and try the
<LS>Copy objects</> function again.

Error message extract from SAP system. Copyright SAP SE.