diff --git a/Codist/Classifiers/CodeTagger.cs b/Codist/Classifiers/CodeTagger.cs
index dd32f7a6..b3a87c9b 100644
--- a/Codist/Classifiers/CodeTagger.cs
+++ b/Codist/Classifiers/CodeTagger.cs
@@ -106,18 +106,25 @@ public IEnumerable<ITagSpan<ClassificationTag>> GetTags(NormalizedSnapshotSpanCo
 				yield break;
 			}
 			IEnumerable<IMappingTagSpan<IClassificationTag>> tagSpans;
-			if (_Tags.LastParsed == 0) {
-				// perform a full parse for the first time
-				Debug.WriteLine("Full parse");
-				tagSpans = _Aggregator.GetTags(new SnapshotSpan(snapshot, 0, snapshot.Length));
-				_Tags.LastParsed = snapshot.Length;
-			}
-			else {
-				var start = spans[0].Start;
-				var end = spans[spans.Count - 1].End;
-				Debug.WriteLine($"Get tag [{start.Position}..{end.Position})");
+			try {
+				if (_Tags.LastParsed == 0) {
+					// perform a full parse for the first time
+					Debug.WriteLine("Full parse");
+					tagSpans = _Aggregator.GetTags(new SnapshotSpan(snapshot, 0, snapshot.Length));
+					_Tags.LastParsed = snapshot.Length;
+				}
+				else {
+					var start = spans[0].Start;
+					var end = spans[spans.Count - 1].End;
+					Debug.WriteLine($"Get tag [{start.Position}..{end.Position})");
 
-				tagSpans = _Aggregator.GetTags(spans);
+					tagSpans = _Aggregator.GetTags(spans);
+				}
+			}
+			catch (ObjectDisposedException ex) {
+				// HACK: TagAggregator could be disposed during editing, to be investigated further
+				Debug.WriteLine(ex.Message);
+				yield break;
 			}
 
 			foreach (var tagSpan in tagSpans) {
diff --git a/Codist/Margins/CodeMarginElement.cs b/Codist/Margins/CodeMarginElement.cs
index b6ec1457..279dc1b6 100644
--- a/Codist/Margins/CodeMarginElement.cs
+++ b/Codist/Margins/CodeMarginElement.cs
@@ -256,6 +256,7 @@ private void DrawMarkers(DrawingContext drawingContext) {
 				}
 				if (b == ClassNameBrush || b == InterfaceNameBrush || b == StructNameBrush || b == EnumNameBrush) {
 					if (tag.Length > 0) {
+						// the tag could be zero-lengthed, so we have to check
 						DrawDeclarationMark(drawingContext, b, y, c, snapshot.GetText(tag.Start, tag.Length));
 					}
 					continue;
diff --git a/Codist/Properties/AssemblyInfo.cs b/Codist/Properties/AssemblyInfo.cs
index beda4f86..199e7484 100644
--- a/Codist/Properties/AssemblyInfo.cs
+++ b/Codist/Properties/AssemblyInfo.cs
@@ -30,4 +30,4 @@
 // by using the '*' as shown below:
 // [assembly: AssemblyVersion("1.0.*")]
 [assembly: AssemblyVersion("2.4.0.0")]
-[assembly: AssemblyFileVersion("2.4.2.439")]
+[assembly: AssemblyFileVersion("2.4.2.443")]
diff --git a/Codist/Views/CSharpTooltip.cs b/Codist/Views/CSharpTooltip.cs
index bdc78975..239c96fc 100644
--- a/Codist/Views/CSharpTooltip.cs
+++ b/Codist/Views/CSharpTooltip.cs
@@ -467,6 +467,7 @@ static StackPanel ToUIText(ImmutableArray<SymbolDisplayPart> parts, string title
 		}
 
 		static void UpdateSyntaxHighlights(IEditorFormatMap formatMap) {
+			System.Diagnostics.Trace.Assert(formatMap != null, "format map is null");
 			_InterfaceBrush = GetFormatBrush(Constants.CodeInterfaceName, formatMap);
 			_ClassBrush = GetFormatBrush(Constants.CodeClassName, formatMap);
 			_TextBrush = GetFormatBrush(Constants.CodeString, formatMap);
@@ -480,7 +481,9 @@ static void UpdateSyntaxHighlights(IEditorFormatMap formatMap) {
 		}
 
 		private void _ConfigUpdated(object sender, EventArgs e) {
-			UpdateSyntaxHighlights(_FormatMap);
+			if (_FormatMap != null) {
+				UpdateSyntaxHighlights(_FormatMap);
+			}
 		}
 		StackPanel ShowAttributes(ImmutableArray<AttributeData> attrs, int position) {
 			var stack = new StackPanel();
diff --git a/Codist/source.extension.vsixmanifest b/Codist/source.extension.vsixmanifest
index 9119332d..02c9b8a4 100644
--- a/Codist/source.extension.vsixmanifest
+++ b/Codist/source.extension.vsixmanifest
@@ -1,7 +1,7 @@
 <?xml version="1.0" encoding="utf-8"?>
 <PackageManifest Version="2.0.0" xmlns="http://schemas.microsoft.com/developer/vsx-schema/2011" xmlns:d="http://schemas.microsoft.com/developer/vsx-schema-design/2011">
     <Metadata>
-        <Identity Id="Codist.WMJ.c7b93d20-621f-4b21-9d28-d51157ef0b94" Version="2.4.2.437" Language="en-US" Publisher="WMJ" />
+        <Identity Id="Codist.WMJ.c7b93d20-621f-4b21-9d28-d51157ef0b94" Version="2.4.2.443" Language="en-US" Publisher="WMJ" />
         <DisplayName>Codist</DisplayName>
         <Description xml:space="preserve">A plugin which enhances coding experience with advanced syntax highlighting and scrollbar marking.
 		
diff --git a/README.md b/README.md
index bd53d49b..8f25b031 100644
--- a/README.md
+++ b/README.md
@@ -30,17 +30,6 @@
   ![Syntax highlight](doc/highlight2.png)
   ![Syntax highlight](doc/highlight3.png)
 
-## Customized comment styles
-* The comment tagger highlights comments (actually all editor styles) to your specific styles.
-
-  ![Comment syntax highlight](doc/comment-tagger-options.png)
-
-  Here's the effect of the highlighted comments.
-
-  ![Comment syntax highlight](doc/syntax-highlight-comments.png)
-
-* The syntax style of comments or C# XML Documentations could be changed too. You can make them semitrasparent to stand behind usual code lines by changing the *Opacity* value of the corresponding syntax parts.
-
 ## Super Quick Info
 
 The quick info (the tooltip shown when you hover your mouse pointer to language elements) can be enhanced by *Codist*.
@@ -69,6 +58,17 @@ The quick info (the tooltip shown when you hover your mouse pointer to language
 
   ![Super Quick Info 6](doc/super-quick-info-6.png)
 
+## Customized comment styles
+* The comment tagger highlights comments to your specific styles.
+
+  ![Comment syntax highlight](doc/comment-tagger-options.png)
+
+  Here's the effect of the highlighted comments.
+
+  ![Comment syntax highlight](doc/syntax-highlight-comments.png)
+
+* The syntax style of comments or C# XML Documentations could be changed too. You can make them semitrasparent to stand behind usual code lines by changing the *Opacity* value of the corresponding syntax parts.
+
 ## Markers on the Scrollbar Margin
 
 The scrollbar can mark...