diff --git a/addons/project_issue/models/project_issue.py b/addons/project_issue/models/project_issue.py
index 526225ac096..5e4a8757d68 100644
--- a/addons/project_issue/models/project_issue.py
+++ b/addons/project_issue/models/project_issue.py
@@ -327,6 +327,19 @@ class ProjectIssue(models.Model):
             self.sudo().write({'date_action_last': fields.Datetime.now()})
         return mail_message
 
+    def _message_post_after_hook(self, message):
+        if self.email_from and not self.partner_id:
+            # we consider that posting a message with a specified recipient (not a follower, a specific one)
+            # on a document without customer means that it was created through the chatter using
+            # suggested recipients. This heuristic allows to avoid ugly hacks in JS.
+            new_partner = message.partner_ids.filtered(lambda partner: partner.email == self.email_from)
+            if new_partner:
+                self.search([
+                    ('partner_id', '=', False),
+                    ('email_from', '=', new_partner.email),
+                    ('stage_id.fold', '=', False)]).write({'partner_id': new_partner.id})
+        return super(ProjectIssue, self)._message_post_after_hook(message)
+
     @api.multi
     def message_get_email_values(self, notif_mail=None):
         self.ensure_one()
diff --git a/addons/project_issue/views/project_issue_views.xml b/addons/project_issue/views/project_issue_views.xml
index b217f68c7b4..383bead65df 100644
--- a/addons/project_issue/views/project_issue_views.xml
+++ b/addons/project_issue/views/project_issue_views.xml
@@ -61,7 +61,7 @@
                 <div class="oe_chatter">
                     <field name="message_follower_ids" widget="mail_followers" groups="base.group_user"/>
                     <field name="activity_ids" widget="mail_activity"/>
-                    <field name="message_ids" widget="mail_thread"/>
+                    <field name="message_ids" widget="mail_thread" options="{'post_refresh': 'recipients'}"/>
                 </div>
                 </form>
             </field>