OpenTween.TweenMain.SetMainWindowTitle C# (CSharp) Method

        private void SetMainWindowTitle()
        {
            //メインウインドウタイトルの書き換え
            StringBuilder ttl = new StringBuilder(256);
            int ur = 0;
            int al = 0;
            if (this._cfgCommon.DispLatestPost != MyCommon.DispTitleEnum.None &&
                this._cfgCommon.DispLatestPost != MyCommon.DispTitleEnum.Post &&
                this._cfgCommon.DispLatestPost != MyCommon.DispTitleEnum.Ver &&
                this._cfgCommon.DispLatestPost != MyCommon.DispTitleEnum.OwnStatus)
            {
                foreach (var tab in _statuses.Tabs.Values)
                {
                    ur += tab.UnreadCount;
                    al += tab.AllCount;
                }
            }

            if (this._cfgCommon.DispUsername) ttl.Append(tw.Username).Append(" - ");
            ttl.Append(Application.ProductName);
            ttl.Append("  ");
            switch (this._cfgCommon.DispLatestPost)
            {
                case MyCommon.DispTitleEnum.Ver:
                    ttl.Append("Ver:").Append(MyCommon.GetReadableVersion());
                    break;
                case MyCommon.DispTitleEnum.Post:
                    if (_history != null && _history.Count > 1)
                        ttl.Append(_history[_history.Count - 2].status.Replace("\r\n", " "));
                    break;
                case MyCommon.DispTitleEnum.UnreadRepCount:
                    ttl.AppendFormat(Properties.Resources.SetMainWindowTitleText1, _statuses.GetTabByType(MyCommon.TabUsageType.Mentions).UnreadCount + _statuses.GetTabByType(MyCommon.TabUsageType.DirectMessage).UnreadCount);
                    break;
                case MyCommon.DispTitleEnum.UnreadAllCount:
                    ttl.AppendFormat(Properties.Resources.SetMainWindowTitleText2, ur);
                    break;
                case MyCommon.DispTitleEnum.UnreadAllRepCount:
                    ttl.AppendFormat(Properties.Resources.SetMainWindowTitleText3, ur, _statuses.GetTabByType(MyCommon.TabUsageType.Mentions).UnreadCount + _statuses.GetTabByType(MyCommon.TabUsageType.DirectMessage).UnreadCount);
                    break;
                case MyCommon.DispTitleEnum.UnreadCountAllCount:
                    ttl.AppendFormat(Properties.Resources.SetMainWindowTitleText4, ur, al);
                    break;
                case MyCommon.DispTitleEnum.OwnStatus:
                    if (followers == 0 && tw.FollowersCount > 0) followers = tw.FollowersCount;
                    ttl.AppendFormat(Properties.Resources.OwnStatusTitle, tw.StatusesCount, tw.FriendsCount, tw.FollowersCount, tw.FollowersCount - followers);
                    break;
            }

            try
            {
                this.Text = ttl.ToString();
            }
            catch (AccessViolationException)
            {
                //原因不明。ポスト内容に依存か？たまーに発生するが再現せず。
            }
        }