User Story

As an app dev, I want to set a tree item as an intermediate state, so that I can show the items' child node being partially selected.

Accept Criteria

1. provide an API to set a tree item as the intermediate state and this API can work correctly with existing API
2. the tree item can display the intermediate state visually in a browser
3. The API can work under MVC and MVVM pattern

Example

see attached example.zip
Tree selection supports 3 states (tri-state):

• all children selected
• none selected
• partial selected