OpenTween.TweenMain.AddTabMenuItem_Click C# (CSharp) Method

        private void AddTabMenuItem_Click(object sender, EventArgs e)
        {
            string tabName = null;
            MyCommon.TabUsageType tabUsage;
            using (InputTabName inputName = new InputTabName())
            {
                inputName.TabName = _statuses.MakeTabName("MyTab");
                inputName.IsShowUsage = true;
                inputName.ShowDialog();
                if (inputName.DialogResult == DialogResult.Cancel) return;
                tabName = inputName.TabName;
                tabUsage = inputName.Usage;
            }
            this.TopMost = this._cfgCommon.AlwaysTop;
            if (!string.IsNullOrEmpty(tabName))
            {
                //List対応
                ListElement list = null;
                if (tabUsage == MyCommon.TabUsageType.Lists)
                {
                    using (ListAvailable listAvail = new ListAvailable())
                    {
                        if (listAvail.ShowDialog(this) == DialogResult.Cancel) return;
                        if (listAvail.SelectedList == null) return;
                        list = listAvail.SelectedList;
                    }
                }

                TabModel tab;
                switch (tabUsage)
                {
                    case MyCommon.TabUsageType.UserDefined:
                        tab = new FilterTabModel(tabName);
                        break;
                    case MyCommon.TabUsageType.PublicSearch:
                        tab = new PublicSearchTabModel(tabName);
                        break;
                    case MyCommon.TabUsageType.Lists:
                        tab = new ListTimelineTabModel(tabName, list);
                        break;
                    default:
                        return;
                }

                if (!_statuses.AddTab(tab) || !AddNewTab(tab, startup: false))
                {
                    string tmp = string.Format(Properties.Resources.AddTabMenuItem_ClickText1, tabName);
                    MessageBox.Show(tmp, Properties.Resources.AddTabMenuItem_ClickText2, MessageBoxButtons.OK, MessageBoxIcon.Exclamation);
                }
                else
                {
                    //成功
                    SaveConfigsTabs();
                    if (tabUsage == MyCommon.TabUsageType.PublicSearch)
                    {
                        ListTab.SelectedIndex = ListTab.TabPages.Count - 1;
                        ListTab.SelectedTab.Controls["panelSearch"].Controls["comboSearch"].Focus();
                    }
                    if (tabUsage == MyCommon.TabUsageType.Lists)
                    {
                        ListTab.SelectedIndex = ListTab.TabPages.Count - 1;
                        var listTab = (ListTimelineTabModel)this._statuses.Tabs[this._curTab.Text];
                        this.GetListTimelineAsync(listTab);
                    }
                }
            }
        }