Completed document

Hello experts

I have a problem finishing my add-on. I have a combo box where you can choose the status of a document. We have 3 status (Completed, in progress, canceled). When selecting "Completed" or "Cancelled" the document should be read only and therefore can not be changed, but when the status is "in progress" adding rows in document line is possible. In general the status on the lines of the document which are in matrix.

Regards.

Olivier