Telerik RadPanelBar ExpandMode property can assume the following values:
MultipleExpandedItems
More than one item can be expanded at a time. If an item is expanded, any previously expanded items will not collapse.
SingleExpandedItem
Only one item can be expanded at a time. If an item is expanded, a previously expanded item will collapse. Also, if there is only one root level item, it cannot be collapsed.
FullExpandedItem
Only one item can be expanded at a time. The expanded area occupies the entire height of the RadPanelBar.
For a demo of the Telerik RadPanelBar expand types, please, see the PanelBar Behavior online example.
See Also