Starting with iOS 7 Apple changed many of the default buttons to remove the outline; now you just tap the word to press the button. There’s a setting hidden in the Accessibility settings that brings back the actual outline of the buttons.
To activate this great feature go to Settings, General, Accessibility, then scroll down to Button Shapes, and turn it on. Now you should see a gray outline where all the buttons are.
In the image above, the left is what Calendar looks like BEFORE turning on Button Shapes, the right side is AFTER. Note the gray boxes.