Imports Infragistics.Win.UltraWinGrid
...
Private Sub UltraGrid1_InitializeLayout(ByVal sender As Object, _
  ByVal e As Infragistics.Win.UltraWinGrid.InitializeLayoutEventArgs) _
  Handles ultraGrid1.InitializeLayout
    ' Set the property on the display layout's override so it affects the whole WinGrid.
    Me.ultraGrid1.DisplayLayout.Override.InvalidValueBehavior = _
      InvalidValueBehavior.RevertValue
    ' You can override the property on a specific column.
    Me.ultraGrid1.DisplayLayout.Bands(0).Columns(0).InvalidValueBehavior = _
      InvalidValueBehavior.RetainValueAndFocus
End Sub