There are two interesting things that I have noticed about transferring the home button on the Air. There seems to be an early version that has a thin metal ring acting as a spacer of sorts inside of the home button assembly. Make sure that if you had one it got transferred to the new lens. Also, insufficient adhesive can be a problem. The long metal piece behind where the button actually clicks should stick securely against the lens. If it doesn't you may get that "sinking" feeling.