Specifies whether the nodes whose parent node is absent in the ASPxTreeListEditor's data source should be displayed as root.
true, if the nodes whose parent node is absent in the data source are displayed as root; otherwise, false. The default value is false.
This property affects what nodes are displayed in a List View represented by the ASPxTreeListEditor, when filtering the List View's ListView.CollectionSource. If the HoldRootValue property is set to true, then after a List View has been filtered so that some parent nodes are now missing, their first-level child nodes will be displayed as root. If the HoldRootValue property is set to false, the child nodes will not be displayed.