 <p>WPF supports two different flavors of focus:</p> <ol> <li>Keyboard focus</li> <li>Logical focus</li> </ol> <p>The <code>FocusedElement</code> property gets or sets logical focus within a focus scope. I suspect your <code>TextBox</code> <em>does</em> have logical focus, but its containing focus scope is not the active focus scope. Ergo, it <em>does not</em> have keyboard focus.</p> <p>So the question is, do you have multiple focus scopes in your visual tree?</p>