3468887 - How to make' Tax code' field mandatory in purchase order

Badi created for purchase order - item field 'tax code' using MM_PUR_S4_PO_FLDCNTRL_SIMPLE , its working for "-" (Hidden) not for "+" (mandatory).

SAP S/4HANA Cloud 

 Refer the KBA https://me.sap.com/notes/3268822

However,Change of Field Control for Purchase Order Items (MM_PUR_S4_PO_FLDCNTRL_SIMPLE) allows you to influence the field control for certain fields. It does not perform any checks that may be required after the change of the status properties.

So use below BAdi as well along with above BAdi to perform your own checks and to output the corresponding error messages on this field.

Check of Purchase Order Before Saving (BD_MMPUR_FINAL_CHECK_PO)

 or

 PO Check All Items  (MM_PUR_S4_PO_CHECK_ALL_ITEMS)

Please check the BADIs on the following  help document link:

https://help.sap.com/docs/SAP_S4HANA_CLOUD/0e602d466b99490187fcbb30d1dc897c/259a396e6bdb4d08b130049880a3920f.html?version=2402.502

S4HC; S4_1C; X4BC; S4_PC; unable to make field as mandatory; , KBA , MM-PUR-PO , Purchase Orders , Problem