jstree从后台取数据加载后，在前台为什么展开不了节点，急啊···在线等

$('#tree_2').jstree({
'plugins': ["wholerow", "checkbox", "types"],
'core': {
"themes" : {
"responsive": false
},
'data': [{
"text": "Same but with checkboxes",
"children": [{
"text": "initially selected",
"state": {
"selected": true
}
}, {
"text": "custom icon",
"icon": "fa fa-warning icon-state-danger",
"state": {
"selected": true
}
}, {
"text": "initially open",
"icon" : "fa fa-folder icon-state-default",
"state": {
"opened": true
},
"children": ["Another node"]
}, {
"text": "custom icon",
"icon": "fa fa-warning icon-state-warning"
}, {
"text": "disabled node",
"icon": "fa fa-check icon-state-success",
"state": {
"disabled": true
}
}]
},
"And wholerow selection"
]
},
"types" : {
"default" : {
"icon" : "fa fa-folder icon-state-warning icon-lg"
},
"file" : {
"icon" : "fa fa-file icon-state-warning icon-lg"
}
}
});