Thanks for your help.
I still have the same isues.

...if (socket_bri === this)
{
// if what is happening is what I believe, this line will rarely be executed. System.print() will confirm.
socket_bri = null;
}

This line is executed very often (each time I scroll the wheel it seems).

The counter of socket is always increasing. It seems the socket_bri.onClose function is never executed and maybe that is the main problem. But I don't understand why it's not executed.