Structure mapping using transaction /AIF/IFB

Hello All,

I am trying to do a simple structure mapping using the transaction /AIF/IFB.

My structure mapping,

               HEADER -> HEADER (mapped)

I mapped FILE_NAME from source to destination as in the below screen, but I could not see the icon(green tick) appearing against the field FILE_NAME in destination structure, but in source this field is in status mapped. Am I missing something here?

Could you please help.

Thanks in advance.