Hi guys,
really many thanks on help to understand well. Now,
"Action: This setting lets you define the if you want the field to be displayed only when the Content Item is being submitted for the first time (Add), or when the Content Item is opened for editing (Edit), or Always for both."
Please, what should happen in case of an administrator pre-imported datas ?
A - The action set read if the field is empty - the administrator imported the datas, so the field is not empty = The Action setting calculate the fied yet Added from the User.
B - The action set read the User bahaviour - the administrator imported the datas, field is not empty but the User haven't click yet on Submit button for the first time (Add) = The Action setting calculate the fied as NO yet Added