Error while deleting segment &

What causes this issue?

An error occurred while trying to delete a segment definition or a
segment. A possible cause is that the segment is still used in IDoc
types.

How to fix this error?

Check if necessary whether the segment is still used in the
<DS:GLOS.3526B583AFAB52B9E10000009B38F974>extensions</> you have
defined, which you no longer require, and delete these.

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

IF DEVICE = 'SCREEN'
<DS:TRAN.WE30>Execute function</>
ENDIF

Error message extract from SAP system. Copyright SAP SE.