zentao/module/group/js/managemember.ui.js

$(function()
{
    $(document).on('change', 'input.check-all', function()
    {
        const checked = $(this).prop('checked');
        $(this).parents('.form-row').find('input[type=checkbox]').prop('checked', checked);
    });

    $(document).on('change', 'input[name^=members]', function()
    {
        let   checked = true;
        const checkedCount = $(this).closest('.form-group').find('input[name^=members]:checked').length;
        const totalCount   = $(this).closest('.form-group').find('input[name^=members]').length;
        if(checkedCount < totalCount) checked = false;

        $(this).closest('.form-row').find('input.check-all').prop('checked', checked);
    });
});