Use
Often customer complain that they have maintained mandatory classification characteristics for a document class type (017), but when they do not enter any value for them the document info record is saved anyway even if error messages CL500 (CV01N, CV02N) or C1821 (if using BAPIs) are raised.
Explanation
First of all mandatory classification fields behave differently than mandatory fields in other applications.
It is possible to save a document info record even if a required characteristic is without value. If a required characteristic has novalue, the system correctly generates the error message CL500. This system behaviour is correct and corresponds to the R/3 standard.
The check for the classification characteristics is performed only in the screen of the 'Additional Data' tab. So when there is a missing mandatory characteristic, the system does not allow you to save on this document. If you switch to the classification tab and SAVE the document the system expects that you do have entered all desired values and saves the document. If you try to save the document without moving explicitly to the classification tab the system thinks that you have forgotton to enter classification values and you can't save the document.
Solution
The SAP notes 906097 and 1000800 will enlarge the checks on the required classification characteristics. But the SAP development encountered serious negative side-effects due to these changes and so the notes 1145858 and 1079992 were created which took back the previous corrections. So the only possible to create a complete check of the entered classification data would be to implement an individual check routine by BADI_DOCUMENT_MAIN01 with method 'BEFORE_SAVE'.