[sylpheed:37339] Filter rules not working for accounts with a space in the name

Hello all,

For me, Filter rules do not work with accouns whose names contain
a space.  For example, I had an account called "Insomnia 24/7".
When tried to create a filter rule to move some messages to:

   #imap/Insomnia 24/7/INBOX

Sylpheed refused to save it, saying the target folder did not
exist. It worked after renamed the account to "Insomnia" .