Problems with large "mailboxes"?

[Raffi Khatchadourian <khatchad@xxxxxxxxxxxxxxxxxx>]

While I'm on the fixing problems kick :) I thought I would discuss a
problem I have been having with offlineimap. My primary mail account is
housed on my UNIX home directory on the primary school server. This
account is not only for mail, it is a general purpose account which
happens to also be a mail account. The problem that I am having is that
offlineimap tries to search the entire account for mail folders, which
are quite minimal compared to the other files in my home directory. As
you can image, this severely degrades the performance of the mail
syncing. Using folder filters seem to help, but not solve the problem.
Here is my folder filter:

folderfilter = lambda foldername: foldername in [
    'INBOX',
    'Drafts',
    'Sent',
    'Trash',
    'Junk',
    ]

Any suggestions? For my other accounts which are *solely* mail accounts,
the performance seems to be fine.