Why files with extension are hidden?

[Ricardo1980]

Hello!
I read in docs:
"The project view will only list resources without a resolution extension. Resources with an extension are hidden."
My iPad game has 2 types of extensions, -ipad and -ipadhd, like:
home_background-ipad.png and home_background-ipadhd.png (one for non retina and the other for retina)
But cocosbuilder hiddes them. Why? I don't understand it. Thanks.