public override async Task OnPageLoad()
        {
            await base.OnPageLoad();

            item1 = new FSW.Semantic.Controls.Html.TabItem("Item1", this);
            item2 = new FSW.Semantic.Controls.Html.TabItem("Item2", this);

            TAB_Test.Tabs.AddRange(new FSW.Semantic.Controls.Html.TabItem[] { item1, item2 });
            TAB_Test.SelectTab(item1);
            TAB_Test.OnSelectedTabChanged += TAB_Test_OnSelectedTabChanged;
            TAB_Test.Inverted              = true;
            FSW.Controls.Html.Div frame1 = item1.Frame;

            item1.Frame.Children.Add(new FSW.Controls.Html.Span(this)
            {
                Text = "Contaner 1",
            });

            item2.Frame.Children.Add(new FSW.Controls.Html.Span(this)
            {
                Text = "Contaner 2",
            });
        }
 private void TAB_Test_OnSelectedTabChanged(FSW.Semantic.Controls.Html.TabItem item)
 {
     MessageBox.Success("title", item.HeaderText);
 }