Putting Away the Keys

Everyday we take the keys out of the drawer to walk down to the mailbox. Well this time Izzy had a particular fascination with the keys. She held them on the way down to the mailbox, held them in the grass, and got upset when it was time to go in, pointing at the mailbox with the keys. So when we got in, I showed her on the door where she could pretend to stick it in and walked away. Paul and I were in the kitchen and she came in, opened the drawer to where the key goes, put the key in, and shut the drawer. How does she know how to do this???