javascript - Angular UI Tree - Allow only drag & drop into second level (children nodes) -

i using angular ui tree.

my object:

     [           {             "id": 1,             "title": "class1",             "students": [               {                 "id": 11,                 "title": "student1.1",               },               {                 "id": 12,                 "title": "student1.2"               }             ]           },           {             "id": 2,             "title": "class2",             "students": []           },           {             "id": 3,             "title": "class3",             "students": [               {                 "id": 31,                 "title": "student3.1"               }             ]           }         ] 

what want achieve allow students drag & drop inside classes (the classes not have draggable, , students not have dropped first level (classes) second level (students)).

is possible achieve angular ui tree?

i made this:

i check in destination scope parent still uitreenode.

in controller:

$scope.treeoptions = {     accept: function(sourcenodescope, destnodesscope, destindex) {          if (destnodesscope.$parent.$type === "uitreenode"){                 return true;         }else{             return false;         }      }   }; 

and in view:

<div ui-tree="treeoptions">