diff --git a/pykolab/imap/__init__.py b/pykolab/imap/__init__.py
--- a/pykolab/imap/__init__.py
+++ b/pykolab/imap/__init__.py
@@ -374,8 +374,8 @@
                     mode = 'subtract'
                     continue
                 if char == '+':
-                    continue
                     mode = 'add'
+                    continue
 
                 acl_map[mode] += char
 
@@ -520,7 +520,7 @@
         _additional_folders = None
 
         if not hasattr(self, 'domain'):
-            self.domain == None
+            self.domain = None
 
         if self.domain == None and len(mailbox_base_name.split('@')) > 1:
             self.domain = mailbox_base_name.split('@')[1]