delete a row in matrix with master data lines

Hi everyBody,

I've created a form with tow parts:

1 : 2 EditText binded with Fields of a Table (OX_ORSTWG) which is Master Data

2 : Matrix which columns binded with a second table (OX_RSTWG1) which is Master Data Lines.

I've created a UDO on this form with the Master Data Table (OX_ORSTWG).

Add, Delete, Modify works perfectly with the Master Data Table.

Inserting and modifing records in the matrix works well also. But I have a problem in deleting rows of the matrix (which represent the second table : Master data lines) .

I don't know why "Delete row" is disabled.

Could someone help me?

Thanks in advance.

Haifa