Drag Reorder
TabControl supports reordering its tab items using drag/drop operations.
To enable the drag reorder feature, set the AllowDragReorder property of RadTabControl to true.
Allow reordering the tab items
<telerik:RadTabControl AllowDragReorder="True">
<telerik:RadTabItem Header="Calendar"/>
<telerik:RadTabItem Header="Colors"/>
<telerik:RadTabItem Header="Quote"/>
</telerik:RadTabControl>