In my application i use TreePanel to contruct tree and do some actions on it ,but when i try to remove node programatically ,some error occurs on javascript(Firebug shows error: "d is null") ,but it removes from tree and user sees that it is really removed ,i cant understand whats wrong
here is my code:

]MDTNodeModel selectedModel = (MDTNodeModel) mdtPanel.getSelectionModel().getSelectedItem();
TreeStore<BaseModel> store = (TreeStore<BaseModel>) mdtPanel.getStore();
List<? extends BaseModel> storeList = store.getAllItems();
store.remove(selectedModel); //Error occurs here i exactly now that selectedModel object is not null
//and also store object