Thank you so much Tanguy, Alfred and Gowtham for all your good answers!
Actually, in the script of my On Select, I was looking at the value of the member selected. In user connected in English, I was looking if my dimension was containing "Overall Result" and if connected in French, if the dimension value was "Résultat global". Indeed, the Overall result line is NOT a line of the member.
Thank you VERY much, this is wrorking fine for me in ALL my crosstab I need to show at top line the Overall resuts.
I would have flag ALL your answers are the correct one, but we can select only ONE. To me, you all have correct answers.
I hope I will be able to help you one day guys!
Again, many thanks!
Regards, Nataly