Hiding or disabling "+" on gridview insert new row

[figueiredorj]

Hi.

I have the following issue: It is intended to allow the user to open Details row only after adding a new row... it can be understood as only on edit...

I will explain it better:
there is the signal "+" that represents GridViewToggleRowDetailsColumn.... I would like it to be visible or enabled only after item row saved.

How can I accomplish this? can someone help me?
thanks