Created Unassigned: Setting Focus in a Tab Panel [27891]

I'm trying to set focus on a text box that's on a tab panel.

I can find the control by using
Dim t As System.Web.UI.WebControls.TextBox = CType(tc1.Tabs(0).FindControl("t1"), TextBox)

but I cannot set focus to the textbox... I get no errors when using t.focus it just won't place the cursor inside the text box

anyone know how to set focus inside a tab panel ?

thanks for your help