Error validation generated form

Thank your response @jgigliotti . I’ve decided to replace the “generated form” with an “embedded form” and I found an example to get the username logged on the Tasklist. I’ve opened a new post How to pass variable value in a form because I can’t pass the value of the variable inside the form. Can you help me ?, I’m not a developer so I move with great difficulty with javascript, AngularJS, …