How to: Adjust the Control's Drag and Drop Options
the following sample code uses the NavBarControl.DragDropFlags property to modify the control’s drag and drop options. It prohibits dropping items from the same control and allows you to drop items from other NavBarControl.
using DevExpress.XtraNavBar;
// ...
navBarControl1.DragDropFlags &= ~NavBarDragDrop.AllowDrop;
navBarControl1.DragDropFlags |= NavBarDragDrop.AllowOuterDrop;