Type: System.Double The rendered width of the row header, in device-independent units (1/96th inch per unit). The registered default is 0.0. For more information about what can influence the value, see DependencyProperty.
This value is computed from the measure of all the visible row headers during layout. The value is set by the layout system itself, based on an actual rendering pass. For more information about how layout is computed, see Layout System.