Strange crash with SpanIndicator when HasFontChange=true

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Text;
using System.Windows.Forms;
using ActiproSoftware.SyntaxEditor;

namespace WindowsApplication1
{
    public partial class Form2 : Form
    {
        public Form2()
        {
            InitializeComponent();
        }

        private void Form2_Load(object sender, EventArgs e)
        {
            editor.Document.Text = "012345678901234567890123456789012345678901234567890123456789";
            editor.Document.SpanIndicatorLayers.Add(new ActiproSoftware.SyntaxEditor.SpanIndicatorLayer("A", 1));

            editor.Document.SpanIndicatorLayers["A"].Add(new QMLSpanIndicator2("B"), new TextRange(10, 20));
            editor.Document.SpanIndicatorLayers["A"].Add(new QMLSpanIndicator2("B"), new TextRange(30, 40));
        }
    }

    public class QMLSpanIndicator2 : SpanIndicator
    {
        public QMLSpanIndicator2(string name)
            : base(name)
        {
        }

        protected override void ApplyHighlightingStyleAdornments(HighlightingStyleResolver resolver)
        {
            if (Name == "S")
            {
                HighlightingStyle hs = new HighlightingStyle("S", "S", Color.Red, Color.Transparent, ActiproSoftware.ComponentModel.DefaultableBoolean.Default, ActiproSoftware.ComponentModel.DefaultableBoolean.Default, HighlightingStyleLineStyle.None);
                hs.StrikeOutStyle = HighlightingStyleLineStyle.Solid;
                resolver.ApplyHighlightingStyleAdornments(hs);
            }
            else if (Name == "U")
                resolver.ApplyHighlightingStyleAdornments(
                    new HighlightingStyle("U", "U", Color.Green, Color.Transparent, ActiproSoftware.ComponentModel.DefaultableBoolean.Default, ActiproSoftware.ComponentModel.DefaultableBoolean.Default, HighlightingStyleLineStyle.Solid)
                );

            base.ApplyHighlightingStyleAdornments(resolver);
        }

        protected override void ApplyHighlightingStyleColors(HighlightingStyleResolver resolver)
        {
            if (Name == "H") resolver.SetBackColor(Color.Yellow);
            base.ApplyHighlightingStyleColors(resolver);
        }

        protected override void ApplyHighlightingStyleFont(HighlightingStyleResolver resolver)
        {
            if (Name == "B") 
                resolver.SetBold(true);
            else if (Name == "I") 
                resolver.SetItalic(true);
            base.ApplyHighlightingStyleFont(resolver);
        }

        public override bool HasFontChange
        {
            get { return true; }
        }

    }
}

System.ArgumentOutOfRangeException was unhandled
  Message="Specified argument was out of the range of valid values.\r\nParameter name: index"
  Source="ActiproSoftware.SyntaxEditor.Net20"
  ParamName="index"
  StackTrace:
       at ActiproSoftware.SyntaxEditor.DocumentLineCollection.get_Item(Int32 index)
       at bl.a(Document A_0, Int32 A_1, TextRange A_2)
       at bl.a(TextRange A_0)
       at ActiproSoftware.SyntaxEditor.SyntaxEditor.b(Object A_0, IndicatorEventArgs A_1)
       at ActiproSoftware.SyntaxEditor.Document.OnIndicatorRemoved(IndicatorEventArgs e)
       at ActiproSoftware.SyntaxEditor.SpanIndicatorLayer.NotifyDocumentTextChanged(DocumentModificationEventArgs e)
       at ActiproSoftware.SyntaxEditor.Document.a(DocumentModification A_0, Boolean A_1)
       at ActiproSoftware.SyntaxEditor.Document.b(DocumentModificationType A_0, Int32 A_1, Int32 A_2, String A_3, DocumentModificationOptions A_4, WeakReference A_5)
       at ActiproSoftware.SyntaxEditor.Document.a(DocumentModificationType A_0, Int32 A_1, Int32 A_2, String A_3, DocumentModificationOptions A_4, WeakReference A_5)
       at ActiproSoftware.SyntaxEditor.EditorView.a(DocumentModificationType A_0, String A_1, DocumentModificationOptions A_2)
       at ActiproSoftware.SyntaxEditor.EditorView.DeleteSelectedText(DocumentModificationType type, DocumentModificationOptions options)
       at ActiproSoftware.SyntaxEditor.Commands.DeleteCommand.Execute(EditCommandContext context)
       at ActiproSoftware.SyntaxEditor.MacroRecording.a(EditCommand A_0, EditCommandContext A_1)
       at ActiproSoftware.SyntaxEditor.EditorView.a(EditCommand A_0, Boolean A_1)
       at ActiproSoftware.SyntaxEditor.SyntaxEditor.a(EditorView A_0, Keys A_1, Char A_2, Boolean A_3)
       at ActiproSoftware.SyntaxEditor.SyntaxEditor.OnKeyDown(KeyEventArgs e)
       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.ScrollableControl.WndProc(Message& m)
       at ActiproSoftware.SyntaxEditor.SyntaxEditor.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.DebuggableCallback(IntPtr hWnd, Int32 msg, IntPtr wparam, IntPtr lparam)
       at System.Windows.Forms.UnsafeNativeMethods.DispatchMessageW(MSG& msg)
       at System.Windows.Forms.Application.ComponentManager.System.Windows.Forms.UnsafeNativeMethods.IMsoComponentManager.FPushMessageLoop(Int32 dwComponentID, Int32 reason, Int32 pvLoopData)
       at System.Windows.Forms.Application.ThreadContext.RunMessageLoopInner(Int32 reason, ApplicationContext context)
       at System.Windows.Forms.Application.ThreadContext.RunMessageLoop(Int32 reason, ApplicationContext context)
       at System.Windows.Forms.Application.Run(Form mainForm)
       at WindowsApplication1.Program.Main() in D:\Dev\New QuestML Editor\WindowsApplication1\Program.cs:line 17
       at System.AppDomain.nExecuteAssembly(Assembly assembly, String[] args)
       at System.AppDomain.ExecuteAssembly(String assemblyFile, Evidence assemblySecurity, String[] args)
       at Microsoft.VisualStudio.HostingProcess.HostProc.RunUsersAssembly()
       at System.Threading.ThreadHelper.ThreadStart_Context(Object state)
       at System.Threading.ExecutionContext.Run(ExecutionContext executionContext, ContextCallback callback, Object state)
       at System.Threading.ThreadHelper.ThreadStart()