Button collapse not working in treeGrid?

Question

I have a problem with collapsing data, but expand work properly. Console was clear and icon arrow(that shows open or closed) is working(change properly too). In what cause may be a problem?

What I do: In first loading I load the root data and all that refer to him. And after clicking I load all that refer to clicked element.

$(document).ready(function () {
    $('#tree').jqGrid({
        'url': '/user/tree',
        'colNames': ['id', 'ФИО', "Телефон", "E-mail", "Профиль"],
        'colModel': [
            {name: 'id', index: 'id', key: true, hidden: true},
            {name: 'name', index: 'name', width: 280},
            {name: 'phone', index: 'phone', width: 130, align: 'right'},
            {name: 'email', index: 'email', width: 220, align: 'right'},
            {name: 'link', index: 'link', align: 'center'}
        ],
        treeGrid: true,
        treeGridModel: 'adjacency',
        ExpandColumn: 'name',
        datatype: "json",
        height: 'auto',
        pager: "#pager"
    })
});

data I got:

{
   "rows":[
      {
         "id":10,
         "cell":{
            "name":"ajlshdjk hdjksdhakjdh",
            "phone":"878971",
            "email":"test@gmail.com7",
            "parent":9,
            "link":"test",
            "level":3,
            "isLeaf":false,
            "expanded":false,
            "id":10
         }
      },
      {
         "id":11,
         "cell":{
            "name":"akjhsdkjgh kdgadkhsgdhkqh",
            "phone":"98712873891",
            "email":"test@gmail.com8",
            "parent":9,
            "link":"test",
            "level":3,
            "isLeaf":false,
            "expanded":false,
            "id":11
         }
      }
   ],
   "records":2,
   "total":1,
   "page":1
}

And server side looks like that:

$level = ++$data['level'];
$nodeid = $data['nodeid'];
$user = User::find($nodeid);

$refs = HelperService::getNextLevelMyRefs($user);

$rows = array();
foreach ($refs as $item) {
    $obj = new \stdClass();
    $obj->id = $item->id;
    $obj->cell = array(
        'name' => $item->firstname . ' ' . $item->lastname,
        'phone' => $item->phone,
        'email' => $item->email,
        'parent' => $item->referer_id,
        'link' => 'test',
        'level' => $level,
        'isLeaf' => $this->checkForRefs($item), //need check
        'expanded' => false,
        'id' => $item->id
    );
    array_push($rows, $obj);
}

Here is a root response from server:

{
  "rows": [
    {
      "id": 7,
      "cell": {
        "name": "sjldhflj sdjfhsjh",
        "phone": "1283918",
        "email": "test@gmail.com4",
        "parent": null,
        "link": "test",
        "level": 0,
        "isLeaf": false,
        "expanded": true,
        "id": 7
      }
    },
    {
      "id": 8,
      "cell": {
        "name": "jsdhfjlash jlhsxjdhjk",
        "phone": "878",
        "email": "test@gmail.com5",
        "parent": 7,
        "link": "test",
        "level": 1,
        "isLeaf": false,
        "expanded": false,
        "id": 8
      }
    }
  ],
  "records": 2,
  "total": 1,
  "page": 1
}

Sorry for incompetence in this question, it my first experience with this library.