Token Collection Error

I am getting the following error in my app. Is there something that would cause the render of SE to try and access a token that doesn't exist in the collection? When the error occurs, the SE window is replaced with the red X, which usually indicates painting failed.

Thanks,

Top Level Exception
Type: System.ArgumentOutOfRangeException
Message: Index was out of range. Must be non-negative and less than the size of the collection.
Parameter name: index
Source: mscorlib
Stack Trace: at System.Collections.ArrayList.get_Item(Int32 index)
at ActiproSoftware.SyntaxEditor.TokenCollection.get_Item(Int32 index)
at ActiproSoftware.SyntaxEditor.TokenCollection._1(Int32 , Int32 )
at ActiproSoftware.SyntaxEditor.EditorView._1(Graphics , Rectangle , DocumentLine , Int32 , DisplayLine , _37 , Rectangle , Int32 )
at ActiproSoftware.SyntaxEditor.EditorView._2(Graphics , Rectangle )
at ActiproSoftware.SyntaxEditor.EditorView.OnRender(PaintEventArgs e)
at ActiproSoftware.WinUICore.UIElement.Render(PaintEventArgs e)
at ActiproSoftware.WinUICore.UIControl.OnRenderChildElements(PaintEventArgs e)
at ActiproSoftware.WinUICore.UIControl.Render(PaintEventArgs e)
at ActiproSoftware.WinUICore.UIControl._1(PaintEventArgs )
at ActiproSoftware.WinUICore.UIControl.OnPaint(PaintEventArgs e)
at System.Windows.Forms.Control.PaintWithErrorHandling(PaintEventArgs e, Int16 layer, Boolean disposeEventArgs)
at System.Windows.Forms.Control.WmPaint(Message& m)
at System.Windows.Forms.Control.WndProc(Message& m)
at System.Windows.Forms.ScrollableControl.WndProc(Message& m)
at ActiproSoftware.SyntaxEditor.SyntaxEditor.WndProc(Message& m)
at System.Windows.Forms.ControlNativeWindow.OnMessage(Message& m)
at System.Windows.Forms.ControlNativeWindow.WndProc(Message& m)
at System.Windows.Forms.NativeWindow.Callback(IntPtr hWnd, Int32 msg, IntPtr wparam, IntPtr lparam)