[OR] .NET framework error at Bentley.Civil.Objects.Engine.ObjectSpace.CheckDisposed()

After creating a new file with my seed, my first steps were to construct a straight line. I clicked the tool for that, then clicked the dropdown list of feature definitions on the feature definition toolbar. I selected the definition I would use. I got a message that I didn't really take notice of, and then I got this error message:

System.InvalidOperationException: The ObjectSpace was previously disposed.
   at Bentley.Civil.Objects.Engine.ObjectSpace.CheckDisposed()
   at Bentley.Civil.Objects.Engine.ObjectSpace.GetObjectSet(ObjectTypeFilter filter, ModelScanningCriteria criteria, Boolean cached)
   at Bentley.Civil.Objects.Engine.ObjectSpace.Bentley.Civil.Objects.IObjectSpace.GetCachedObjectSet(Type type, Boolean inActiveModel)
   at Bentley.Civil.Objects.Encapsulation.ObjectSpaceEncapsulation.GetCachedObjectSet(Type type, Boolean inActiveModel)
   at Bentley.Civil.Model.CivilModel.GetCivilModel(IObjectSpace objSpace, Boolean acceptInactive, Boolean createIfDontExist, Boolean inRootModelIfAllowDontExist)
   at Bentley.Civil.Model.CivilModel.GetOrCreateDataSetModel[T](IObjectSpace objectSpace, IDataSetModelFactory`1 datasetModelFactory, Boolean createIfDontExist, Boolean allowDontExist, Boolean acceptInactive, Boolean inRootModelIfAllowDontExist)
   at Bentley.Civil.Model.ContentManagement.ContentManagementModel.GetContentManagementModel(IObjectSpace objectSpace, Boolean createIfDontExist, Boolean allowDontExist, Boolean acceptInactive, Boolean inRootModelIfAllowDontExist)
   at Bentley.Civil.Model.ContentManagement.ContentManagementModel.GetContentManagementModelAndAllowDontExist(IObjectSpace objectSpace)
   at Bentley.Civil.Model.ContentManagement.ContentManagementManager.SetContentManagementModel(IObjectSpace objectSpace, Boolean acceptInactive, Boolean createIfDontExist, Boolean allowDontExist)
   at Bentley.Civil.Model.ContentManagement.ContentManagementManager.LoadCurrent(Boolean createCivilModel, IObjectSpace objectSpace)
   at Bentley.Civil.Model.ContentManagement.ContentManagementManager.GetActiveFeatureDefinition(IObjectSpace objectTracker)
   at Bentley.Civil.Geometry.Command.FeaturizedGeometryCommand.ActiveFeatureDefinitionChanged(Object sender, ActiveFeatureDefinitionChangeEventArgs e)
   at Bentley.Civil.Geometry.Command.FeaturizedGeometryCommand.FeatureDefinitionOverrideChanged(Object sender, FeatureDefinitionOverrideChangeEventArgs e)
   at System.EventHandler`1.Invoke(Object sender, TEventArgs e)
   at Bentley.Civil.Model.ContentManagement.ContentManagementManager.set_FeatureDefinitionOverride(Boolean value)
   at Bentley.Civil.Commands.Geometry.GeometryToggleToolBar.m_activeFeatureOverrideToggle_Click(Object sender, EventArgs e)
   at System.Windows.Forms.ToolStripItem.RaiseEvent(Object key, EventArgs e)
   at System.Windows.Forms.ToolStripButton.OnClick(EventArgs e)
   at System.Windows.Forms.ToolStripItem.HandleClick(EventArgs e)
   at System.Windows.Forms.ToolStripItem.HandleMouseUp(MouseEventArgs e)
   at System.Windows.Forms.ToolStripItem.FireEventInteractive(EventArgs e, ToolStripItemEventType met)
   at System.Windows.Forms.ToolStripItem.FireEvent(EventArgs e, ToolStripItemEventType met)
   at System.Windows.Forms.ToolStrip.OnMouseUp(MouseEventArgs mea)
   at System.Windows.Forms.Control.WmMouseUp(Message& m, MouseButtons button, Int32 clicks)
   at System.Windows.Forms.Control.WndProc(Message& m)
   at System.Windows.Forms.ScrollableControl.WndProc(Message& m)
   at System.Windows.Forms.ToolStrip.WndProc(Message& m)
   at Bentley.UI.Controls.WinForms.ToolBoxToolStrip.WndProc(Message& m)
   at Bentley.Civil.UI.Controls.CivilToolBoxToolStrip.WndProc(Message& m)
   at System.Windows.Forms.Control.ControlNativeWindow.OnMessage(Message& m)
   at System.Windows.Forms.Control.ControlNativeWindow.WndProc(Message& m)
   at System.Windows.Forms.NativeWindow.Callback(IntPtr hWnd, Int32 msg, IntPtr wparam, IntPtr lparam)

Running Geopak SS4 .878. It is not immediately fatal.