Problem when creating PO ME21N

Hi after we upgraded our system from 4.6C to ECC 6.0.,
we can no longer see the material number in PO screen (ME21N), also you basically can not create PO since whenever you enter the material number during PO creation, systm will pop up an error message "Please enter material number or account assignemnt" Message no 06026.

The solution is to adjust the configuration - IMG - Materials Management->Purchasing->Purchase Order->Define Screen Layout at Document Level..

Now the trick is to make sure you set the Material Field (in the Enjoy Fields) section to "Opt Entry" - but make sure you set it for ME21N, AKTH and NBF. I found that the purchase order transaction ME21N combines the settings from these three variants. Since NBF is the default screen variant (if no other is assigned to the order type you're using), the settings from NBF will over-ride those against ME21N. (check any custom variants you are using also). The behaviour is different from previous versions of SAP (4.6c in our case)

Table control administration is limited in ME21N/ME22N - it is only possible to move columns to the far right if you want to hide them. There is a note about that somewhere.