The sample shows behavior of the 'custom' clipboard which allow users to specify a custom logic for the insert operation. The mode can be characterized as follows:

1) When you use ctrl+c , data is copied to the clipboard.

2) When you use ctrl+v, DataTree invokes the onPaste event. You can handle this event to set a custom logic.

By default, the handler doesn't do anything

Press CTRL+C to copy an item from the textarea. Then, select some node in DataTree and press Ctrl+V (note, in the current sample the onPaste handler just alerts messages and doesn't change DataTree items).