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;
}
}