Tableau count number of row wrong without specific dimension

Hello everybody

I would like to count number of activation as displayed in column 'number_of_activation' without the need to display column 'transaction_id'.

Here's my current result  :

So the result should be for each 'user_id', his number_of_activation and his number_of_transaction. But the calculated field in number_of_activation is wrong and I get transaction_id field off the dashboard.

Here's the content of my calculated field number_of_activation

{ FIXED [transaction_id (Requête SQL personnalisée)] : COUNT([Activator Id])}