fix the problem with history tables as table children (#335)

src/Microsoft.SqlTools.ServiceLayer/ObjectExplorer/SmoModel/SqlHistoryTableQuerier.cs

@@ -0,0 +1,23 @@
+//
+// Copyright (c) Microsoft. All rights reserved.
+// Licensed under the MIT license. See LICENSE file in the project root for full license information.
+//
+
+using Microsoft.SqlServer.Management.Smo;
+
+namespace Microsoft.SqlTools.ServiceLayer.ObjectExplorer.SmoModel
+{
+    /// <summary>
+    /// Filters the history tables to only return ones related to the parent table
+    /// </summary>
+    internal partial class SqlHistoryTableQuerier : SmoQuerier
+    {
+        protected override bool PassesFinalFilters(SqlSmoObject parent, SqlSmoObject smoObject)
+        {
+            Table parentTable = parent as Table;
+            Table historyTable = smoObject as Table;
+
+            return (parentTable.HistoryTableID == historyTable.ID);
+        }
+    }
+}