Jurgen Sir ,
I'm pretty sure about it to change as " supplying plant " from " vendor " - 'cause , when I choose UB , doc type , the screen field appears as usual - like , supplying field .
That's why I got strange how it occurred and posted here to ask for help .
Actually , it's payable online IDES network - a lot of persons are using , so I'm not sure who actually did it !! ...
Anyway , now how can I change it as normal one ?