OR SS3 .NET Framework error scanning through DependsOn elements

************** Exception Text **************
System.NullReferenceException: Object reference not set to an instance of an object.
   at Bentley.Civil.Geometry.Model.ComplexLinElemToLinearEntity2dRule.AddGeometryTagsForEntity(List`1 tags, String tagBaseName, Int32& index, DirectionEnum direction, LinearEntity2d entity, LinearElement testGeometry)
   at Bentley.Civil.Geometry.Model.ComplexLinElemToLinearEntity2dRule.GetValidGeometryTags(List`1& tags, LinearElement testGeometry)
   at Bentley.Civil.Geometry.Model.ComplexLinElemToLinearEntity2dRule.GetValidGeometryTags()
   at Bentley.Civil.Geometry.Model.ComplexLinElemToLinearEntity2dRule.GetGeometryTagsForSubLinearComponent(LinearEntity2dInPlan subObject)
   at Bentley.Civil.Geometry.Presentation.NavLinearEntity2dInPlan.SubComponentIndexes()
   at Bentley.Civil.CadSystem.Microstation.MstnNavObject.HiliteOrDehilite(Boolean hiliteIn)
   at Bentley.Civil.CadSystem.Microstation.MstnNavObject.Hilite()
   at Bentley.DesignExplorer.NavigatorNode.HiliteDomainObject()
   at Bentley.DesignExplorer.ElementExplorer.SelectionProvider.AddToSelection(NavigatorTree treeIn, List`1 navigatorNodesIn)
   at Bentley.DesignExplorer.NavigatorTree.MultiSelectAddCallback(Object senderIn, MultiSelectTreeViewEventArgs eventArgsIn)
   at Bentley.UI.Controls.WinForms.MultiSelectTreeView.OnMultiSelectAdd(MultiSelectTreeViewEventArgs eventArgsIn)
   at Bentley.UI.Controls.WinForms.MultiSelectTreeView.ProcessNodeSelection(TreeNode treeNodeIn, Boolean controlModifierOnIn, Boolean shiftModifierOnIn, TreeViewAction actionTypeIn)
   at Bentley.UI.Controls.WinForms.MultiSelectTreeView.OnKeyDown(KeyEventArgs eventArgsIn)
   at System.Windows.Forms.Control.ProcessKeyEventArgs(Message& m)
   at System.Windows.Forms.Control.ProcessKeyMessage(Message& m)
   at System.Windows.Forms.Control.WmKeyChar(Message& m)
   at System.Windows.Forms.Control.WndProc(Message& m)
   at System.Windows.Forms.TreeView.WndProc(Message& m)
   at Bentley.UI.Controls.WinForms.MultiSelectTreeView.WndProc(Message& messageIn)
   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)

This showed up unexpectedly as I was hitting the keyboard's down arrow scanning through elements in the Element Information pane. After clicking to continue, everything seems to be operating normally, and I haven't yet been able to duplicate the error.

Power Geopak SS3 .722.