Tabindex Problem in AutoComleteBox.

Hi,

I am creating simple WPF form application. I have 2 AutoCompleteBox and 1 TextBox on my form,

I have set tab index 1 for autoCompleteBox1, tab index 2 for textBox1 and tab index 3 for autoCompleteTextBox2.

Now whenever I ran my application it does not follow tab index as I have allocated to it. It directly focuses on autoCompleteBox2 instead of textBox1. Logically it needs to focus on textBox1.

Thanks in advance.