The control supports multiple selection but there does not appear to be a programatic way to set the selected state on more than a single node.
Setting the SelectedNodes property with an array of nodes "to be selected" causes very odd behavior. Ther must be some other, correct, way to do this.
Any hints anyone?
To select nodes from code you should do this:
In order for this to work the TreeViewAdv.MultipleNodeSelection must be set to true.
The results might not be visible if the Tree hasn`t got focus. To fix this you should set the HideSelection property to false.