SAP Note 24985 - Display messages: Back causes error VN003

Symptom:

Exiting the header, messages with the green arrow causes the error
E: Please enter partner function! (message: VN003)

Cause and prerequisites

If a message contains a partner-specific output type, where the default value for the partner function is removed in the message type, then error message VN003 occurs when you leave screen SAPDV70A 100 using the green arrow.
This is caused by incorrect flow logic in the screen concerning value transfer between the structures DNAST and NAST

Solution
Correction in screen SAPDV70A 100
changed program code is marked with (<-----)