Look to see if the view hierarchy has become messed up. You can easily see this in the 'document outline.'
If you don't see this pane, look on the left, bottom side of the storyboard and click the small arrow pointing to the left.
What do you see here? Is the Text Field an immediate child of the View or of something else? If it's an immediate child, do you see other children of View listed here that you don't recognize?