default_controller ignores case

[eluser]Unknown[/eluser]
Using version 1.6.1 of CI

As a default controller I can't use a controller with a Uppercase filename
so show.php will work while Show.php won't regardless if I specify "show" or "Show" in routes.php

[eluser]Tanque[/eluser]
the name of the controller can be in capitalize... but the name of the file must be in lowercase...