diff --git a/golem_season/__openerp__.py b/golem_season/__openerp__.py
index 63c5780..14c2f50 100644
--- a/golem_season/__openerp__.py
+++ b/golem_season/__openerp__.py
@@ -27,6 +27,6 @@
     'license': 'AGPL-3',
     'application': False,
     'installable': True,
-    'depends': ['base'],
+    'depends': ['membership'],
     'data': ['views/golem_season_view.xml']
 }
diff --git a/golem_season/models/golem_season.py b/golem_season/models/golem_season.py
index 474cdab..cecb0f2 100644
--- a/golem_season/models/golem_season.py
+++ b/golem_season/models/golem_season.py
@@ -58,15 +58,19 @@ class GolemSeason(models.Model):
 
     @api.one
     def do_default_season(self):
-        """ is_default on and ensure that only one is_default is active """
+        """ is_default on and ensure that only one is_default is active. Also
+        recomputes is_current for members and activities. For simplicity use a
+        magic trick around registry rather than double inheritance """
         old_default_season = self.search([('is_default', '=', True)])
         if old_default_season:
             old_default_season.is_default = False
         self.is_default = True
-        all_members = self.env['golem.member'].search([])
-        all_members._compute_is_current()
-        all_members._compute_number()
-        self.env['golem.activity'].search([])._compute_is_current()
+        if 'golem.member' in self.env.registry:
+            all_members = self.env['golem.member'].search([])
+            all_members._compute_is_current()
+            all_members._compute_number()
+        if 'golem.activity' in self.env.registry:
+            self.env['golem.activity'].search([])._compute_is_current()
 
     @api.multi
     def unlink(self):