case-insensitive file extensions

[Rob Burns]

In NSWorkspace the methods concerned with selecting icons, and apps for files 
with a given extension operate as if extensions were case insensitive. There 
are comments to the effect that they are supposed to be case-insensitive. But, 
I couldn't find this in the documentation anywhere. My question is, should apps 
wanting to do checks on a file extension, always assume that they could be 
getting either a .ZIP file or a .zip file. (because an app that advertises for 
just .zip files could recieve both) or should NSOpenPanel, gopen, and 
GWorkspace be providing filenames with only lowercase extensions, as extensions 
are supposed to be case-insensitive. Currently those three places provide the 
actual filename, preserving the case of the extension.

Thanks,
Rob