The problem is that you misspelled the property "children" (you have written "Children"). Correct that and you will see the children.
Also you might consider adding an ID for every node.
Вопрос
I created a sample of ExtJS tree grid. But the grid is showing only the root node. Please check this fiddle and let me know why the remaining nodes are not visible.
Решение
The problem is that you misspelled the property "children" (you have written "Children"). Correct that and you will see the children.
Also you might consider adding an ID for every node.