Remember to clear the history log and run a repaint when an update is received.

src/GitHub.Unity/Assets/Plugins/GitHub/Editor/Window.cs

@@ -305,7 +305,9 @@ namespace GitHub.Unity
 
 		void OnLogUpdate(IList<GitLogEntry> entries)
 		{
+			history.Clear();
 			history.AddRange(entries);
+			Repaint();
 		}