GETWA_NOT_ASSIGNED dump in sap

Hi experts,

I have a problem with ALV list.

The case is like below.

1. I added a new field that length is 6 with CHAR type.
   1. It was okay. There was no problem with just adding a field.
2. I added thefield with the attribute "EDIT = 'X'".
   1. In this case, the GETWA_NOT_ASSIGNED dmp occurs.

Everything is the same execpt EDIT attribute.

I need to set the field as editable so is there any solutions for this case?

Thanks.