Fix thread-safety and interface compliance issues

src/Infrastructure.VS/DocumentEvents/ActiveDocumentTracker.cs

@@ -93,26 +93,26 @@ public ActiveDocumentTracker(
         ///
         /// To support all the cases, we use SEID_DocumentFrame for uses cases 1-3 and SEID_WindowFrame for use case 4.
         /// </summary>
-        int IVsSelectionEvents.OnElementValueChanged(uint elementId, object oldValue, object newValue)
+        int IVsSelectionEvents.OnElementValueChanged(uint elementid, object varValueOld, object varValueNew)
         {
             threadHandling.ThrowIfNotOnUIThread();
 
-            if (elementId == (uint)VSConstants.VSSELELEMID.SEID_DocumentFrame)
+            if (elementid == (uint)VSConstants.VSSELELEMID.SEID_DocumentFrame)
             {
                 ITextDocument activeTextDoc = null;
 
-                if (newValue is IVsWindowFrame newWindowFrame)
+                if (varValueNew is IVsWindowFrame newWindowFrame)
                 {
                     activeTextDoc = textDocumentProvider.GetFromFrame(newWindowFrame);
                 }
 
                 // The "active document" will be null if the last document has just been closed
                 NotifyActiveDocumentChanged(activeTextDoc);
             }
-            // if we reached here, we know that oldValue and/or newValue are a tool window,
+            // if we reached here, we know that varValueOld and/or varValueNew are a tool window,
             // and we are only interested in the use case of [tool window] -> [doc]
-            else if (elementId == (uint) VSConstants.VSSELELEMID.SEID_WindowFrame &&
-                     newValue is IVsWindowFrame newWindowFrame && IsDocumentFrame(newWindowFrame))
+            else if (elementid == (uint) VSConstants.VSSELELEMID.SEID_WindowFrame &&
+                     varValueNew is IVsWindowFrame newWindowFrame && IsDocumentFrame(newWindowFrame))
             {
                 var activeTextDoc = textDocumentProvider.GetFromFrame(newWindowFrame);
                 NotifyActiveDocumentChanged(activeTextDoc);

src/IssueViz/Editor/ErrorTagging/ErrorTagTooltipProvider.cs

@@ -20,6 +20,7 @@
 
 using System;
 using System.ComponentModel.Composition;
+using System.Threading;
 using System.Windows;
 using System.Windows.Controls;
 using System.Windows.Documents;
@@ -94,12 +95,17 @@ public object Create(IAnalysisIssueBase analysisIssueBase)
                 Foreground = GetVsThemedColor(EnvironmentColors.SystemCaptionTextBrushKey)
             };
 
-            instanceCount++;
-            logger.LogVerbose($"[ErrorTagTooltipProvider] tooltip instance count: {instanceCount}");
+            var currentCount = IncrementInstanceCount();
+            logger.LogVerbose($"[ErrorTagTooltipProvider] tooltip instance count: {currentCount}");
 
             return content;
         }
 
+        private static long IncrementInstanceCount()
+        {
+            return Interlocked.Increment(ref instanceCount);
+        }
+
         private static void ApplyHyperlinkStyle(Hyperlink hyperlink)
         {
             // Style the hyperlink to behave like other error tooltips i.e.

src/IssueViz/IssueVisualizationControl/ViewModels/IssueVisualizationViewModel.cs

@@ -304,7 +304,8 @@ private IReadOnlyList<ILocationListItem> BuildLocationListItems(IAnalysisIssueFl
 
             if (flowLocations != null && flowLocations.Any())
             {
-                for (var i = 0; i < flowLocations.Count; i++)
+                var i = 0;
+                while (i < flowLocations.Count)
                 {
                     var location = flowLocations[i];
 
@@ -317,7 +318,7 @@ private IReadOnlyList<ILocationListItem> BuildLocationListItems(IAnalysisIssueFl
 
                     listItems.AddRange(sequentialLocations.Select(x => (ILocationListItem)new LocationListItem(x)));
 
-                    i += sequentialLocations.Count - 1;
+                    i += sequentialLocations.Count;
                 }
             }