When using seafile as sole storage provider, I get all available repos listed and the files on the root level but no subfolders are queries.
On the oppsite, when using seafile as addon driver subfolders are correctly loaded and shown.
root@mx01:/etc/roundcubemail# dpkg -l | egrep "kolab.files|chwala"
ii chwala 0.5.5-0~kolab2 all Glorified WebDAV, done right
ii roundcubemail-plugin-kolab-files 1:3.4.3-0~kolab3 all kolab_files plugin for Roundcube
Currently digging into the code. But it must have something to do with the way repos and folders are threated on root level or in a storage-driver-folder (when used as addon and repos are already considered like a subfolder in the treeview)