here is the server error

Traceback (most recent call last):

  File "/home/odoo/src/odoo/8.0/openerp/http.py", line 544, in _handle_exception return super(JsonRequest, self)._handle_exception(exception) File "/home/odoo/src/odoo/8.0/openerp/http.py", line 581, in dispatch result = self._call_function(**self.params) File "/home/odoo/src/odoo/8.0/openerp/http.py", line 317, in _call_function return checked_call(self.db, *args, **kwargs) File "/home/odoo/src/odoo/8.0/openerp/service/model.py", line 118, in wrapper return f(dbname, *args, **kwargs) File "/home/odoo/src/odoo/8.0/openerp/http.py", line 314, in checked_call return self.endpoint(*a, **kw) File "/home/odoo/src/odoo/8.0/openerp/http.py", line 810, in __call__ return self.method(*args, **kw) File "/home/odoo/src/odoo/8.0/openerp/http.py", line 410, in response_wrap response = f(*args, **kw) File "/home/odoo/src/odoo/8.0/addons/web/controllers/main.py", line 944, in call_kw return self._call_kw(model, method, args, kwargs) File "/home/odoo/src/odoo/8.0/addons/web/controllers/main.py", line 936, in _call_kw return getattr(request.registry.get(model), method)(request.cr, request.uid, *args, **kwargs) File "/home/odoo/src/odoo/8.0/openerp/api.py", line 268, in wrapper return old_api(self, *args, **kwargs) File "/home/odoo/src/odoo/8.0/openerp/models.py", line 2093, in read_group assert groupby_def and groupby_def._classic_write, "Fields in 'groupby' must be regular database-persisted fields (no function or related fields), or function fields with store=True"AssertionError: Fields in 'groupby' must be regular database-persisted fields (no function or related fields), or function fields with store=True

And here is the filter leading to the above error

Nom du Filtre    filtre by public cat    

Utilisateur

Modèle    Product Template

Default filter

Action   Products

Domaine    [['sale_ok', '=', 1], ['public_categ_ids', '!=', False]]

Contexte    {'group_by': ['public_categ_ids']}