I am building a field catalog for ALV hierarchical list in my program. So, I am passing two internal tables , one for header level and another for position level. After the second call to FM "REUSE_ALV_FIELDCATALOG_MERGE" for adding Position level internal table fields to field catalog, field catalog has one less field. The internal table of Header level has 90 fields and Position level has 31 fields. After the call to FM twice, field catalog has only 120 fields instead of 121 fields and this is throwing a run time error with "TABLE_INVALID_INDEX" when I try to execute the program.
The position level internal table looks like this(just an example):
data: BEGIN OF T_POS OCCURS 0,
MATNR like VAPMA-MATNR.
include structure VBAK.
data: end of T_POS.
So, The field catalog gets added with the fields of structure VBAK but not MATNR.
Can some one give me clue why the field catalog is not taking up one field? I would appreciate if some one can let me know.