I\'m using more than one TabContainer on a page in an ASP.NET project and I noticed a really strange behavior: when the page is loaded the focus jumps to the last TabContain
You can set focus server-side to avoid the page jumping around.
Try this in Page_Load:
PageUtility.SetFocus(foo);
Also check you whether you are setting Page.MaintainScrollPositionOnPostback.
Let me know if that helps.
UPDATE - you can simply call .Focus() on whatever control you want to be in focus by default.
eg: YourControlToFocus.Focus()