AutoSelectBehavior: Controled by the "AutoSelectBehavior" property, the content of the AutoSelectTextBox will be selected or not when the control get the focus. AutoMoveFocus: Effect with "MaxLength" property: Setting the "MaxLenght" of the text box allow the focus to move from the AutoSelectTextBox once the max lenght has been reached. In the following "Telephone Number" fields, the "MaxLenght" property of the control has been set to 3, 3 and 4, respectively Effect with Arrow keys The "AutoMoveFocus" at true also allow to navigate the focus thru the controls using the arrow keys to move the focus up, down, left or right. You are no longer limited to the "left-right" scenario of the "Tab, Shift-Tab" keys.