Hi,
You have to clear the tabpages and re-add them in the desired order.
this.tabControlAdv1.TabPages.Clear();
this.tabControlAdv1.TabPages.AddRange(new TabPageAdv[]
{
this.tabPageAdv4,
this.tabPageAdv3,
this.tabPageAdv2,
this.tabPageAdv1
});
Thanks,
Mano