[Dovecot] renaming and select failes

Hello,

I created a folder inbox.Test.Try through IMAP. LIST shows me the folder INBOX.Test.Try instead, but in the filesystem it's created inbox.Test.Try. Now every select, examine or rename gives me

NO Mailbox doesn't exist INBOX.Test.Try.

Seems that inbox is mapped uppercase everywhere except at "create".

Regards Marten