Need help identifying invisible buttons

In my game, whenever I hit Enter, I can hear the GUI click sound. However I for the love of God can not find this button. Is there an event I can hear or something that can help me determine this button? I have a lot of buttons in my app (it’s quite complex).
https://www.google.com.vn/

The static method “PGItem.getFocusItem()” may help: it returns the PGItem that currently has focus, according to the documentation.