Results.DB change : SessionFactory erased only when the new connection string differs from the previous one.

Results/DB.cs

@@ -21,12 +21,19 @@ namespace Results
 		public static ISessionFactory SessionFactory;
 
 		/// <summary> Connection string for all sessions </summary>
-		private static string connectionString;
+		static string connectionString;
 		/// 
 		public static string ConnectionString
 		{
 			get { return connectionString; }
-			set { connectionString = value; SessionFactory = null; }
+            set
+            {
+                if (value != connectionString)
+                {
+                    connectionString = value;
+                    SessionFactory = null;          /// Clear SessionFactory on connection string change
+                }
+            }
 		}
 
 		/// <summary> Database type (MySQL or SQLite) for all sessions </summary>