AjaxControlToolkit.TabContainer.OnInit C# (CSharp) Method

        protected override void OnInit(EventArgs e)
        {
            base.OnInit(e);

            Page.RegisterRequiresControlState(this);
            _initialized = true;

            if(_cachedActiveTabIndex > -1) {
                ActiveTabIndex = _cachedActiveTabIndex;
                if(ActiveTabIndex < Tabs.Count)
                    Tabs[ActiveTabIndex].Active = true;
            } else if(Tabs.Count > 0) {
                ActiveTabIndex = 0;
            }
        }