[RCU] Folder limit

Is there a limit on the number of folders Roundcube can work with? When I go to the folders list in my primary mail account it sits loading for a while and then ends up with a blank page. I am assuming I have too many folders for Roundcube to work with. Either that or the fact that I have folders within folders is causing problems.

I have 1311 folders at present with the archives that all sit below an archive folder. All works fine with Thunderbird accessing the folders via IMAP and Mutt directly on the server. I am using Dovecot for IMAP access.