Why is the childRow disapearing when I use Col Priorities

Legollas

This is the code I am using:

var fillTable= function (data) {

    var list = [
         { name: 'Name 123456789', email: "email@email.com"},
         { name: 'Name 123456789_10', email: "email@email.com"},
         { name: 'Name 123456789_11', email: "email@email.com"},
         { name: 'Name 123456789_12', email: "email@email.com"},
         { name: 'Name 123456789_13', email: "email@email.com"}
    ];

    var tableToFill= $('#js-table').DataTable({
        responsive: true,
        columnDefs: [
            { responsivePriority: 1, targets: 1 }
            ],
        columns: [
            { data: "name", title: "Name" },
            { data: "email", title: "Email" }
        ],
        language: localiseDataTable(),
        order: [[0, 'desc']]
    });

    tableToFill.clear();
    tableToFill.rows.add(list);
    tableToFill.draw(false);
    tableToFill.columns.adjust().responsive.recalc();
}

Can someone explain me why when I shrink the screen the "Plus" sign does not appear when I use : { responsivePriority: 1, targets: 1 }. This makes impossible to see the childRow and by consequence to see the first column data in low resolution screens.

Thanks in advance