[Mono-list] Medsphere Graph Crashes When Clicked

[Adam Tauno Williams]

I have an app creating a graph using Medsphere.  The graph appears, at
least the axes do, but no plot appears (although the vertical range
appears to be what I expected.)  And it crashes if I click on the graph:

Exception in Gtk# callback delegate
  Note: Applications can use GLib.ExceptionManager.UnhandledException to
handle the exception.
System.NullReferenceException: Object reference not set to an instance
of an object
  at Medsphere.Widgets.HistogramPlot.GetPlotPoint (TreeIter iter,
System.Int32& x, System.Int32& y) [0x00000] 
  at Medsphere.Widgets.HistogramPlot.GetGrabFocusRequest (System.Int32&
x, System.Int32& y) [0x00000] 
  at Medsphere.Widgets.Graph.OnFocusGrabbed () [0x00000] 
  at Gtk.Widget.focusgrabbed_cb (IntPtr widget) [0x00000] 
   at GLib.ExceptionManager.RaiseUnhandledException(System.Exception e,
Boolean is_terminal)
   at Gtk.Widget.focusgrabbed_cb(IntPtr widget)
   at Gtk.Widget.gtk_widget_grab_focus(IntPtr )
   at Gtk.Widget.GrabFocus()
   at Medsphere.Widgets.Graph.OnFocusInEvent(Gdk.EventFocus focus)
   at Gtk.Widget.focusinevent_cb(IntPtr widget, IntPtr evnt)
   at Gtk.Widget.gtksharp_widget_base_grab_focus(IntPtr )
   at Gtk.Widget.OnFocusGrabbed()
   at Medsphere.Widgets.Graph.OnFocusGrabbed()
   at Gtk.Widget.focusgrabbed_cb(IntPtr widget)
   at Gtk.Widget.gtk_widget_grab_focus(IntPtr )
   at Gtk.Widget.GrabFocus()
   at Medsphere.Widgets.Graph.OnButtonPressEvent(Gdk.EventButton ev)
   at Medsphere.Widgets.Graph2D.OnButtonPressEvent(Gdk.EventButton ev)
   at Gtk.Widget.buttonpressevent_cb(IntPtr widget, IntPtr evnt)
   at Gtk.Application.gtk_main()
   at Gtk.Application.Run()
   at MorrisonIndustries.IMAPAnalysis.App.Main(System.String[] args)

Anyone seen this before?