change the subject of the selected mail

[Choubisoft]

Good evening,
I need to change the subject of an e-mail received, when I click on a button. I esseyer is the code below but unfortunately it yielded no results.

/**
 * Shows and chang the subject of the selected mail.
 * 
 */

com_zimbra_c_mail_info_HandlerObject.prototype._showSelectedMail =
function(controller) {


	var msg = controller.getMsg();
	var newSbj = "My String " + msg.subject;
	controller._setSubject(null, msg, newSbj);


	this._displayDialog();
	
};

If you like it if you have any ideas I would appreciate it.
Thank you in advance.

[Choubisoft]

UP Plz ...