This sample explains you about the multiple item selection functionalities of the Dropdown Tree. To select multiple items, you may press and hold the CTRL key and then select the desired items; or select any item by selecting it and then press and hold the SHIFT key to select a range of items continuously.
The Dropdown Tree control allows you to select multiple items by enabling the
AllowMultiSelection property.
In this demo, the Dropdown Tree is enabled with multiple selection.