ability to prevent background section to disepear

[gertcuykens]

http://www.polymer-project.org/components/core-animated-pages/demos/music.html

When you change the .card height in chrome console you will see that the small card tiles in the background hiding behind the big card, suddenly disappear completely when the animation is done.

Is there a way to tell a hero transition to not remove the parent section? Or a way to make the parent section disappear but gradually?

In this case it is ok because you don't see them disappear but when the background has a number of small cards that do not fit behind the large card it would look way better if they just stay in the background.

(http://stackoverflow.com/questions/25840794/hero-transition-background-disappears)