[IMP] Checking only one selected sales channel

pms/models/pms_folio.py

@@ -674,3 +674,10 @@ class PmsFolio(models.Model):
             (line[0].name, line[1]["amount"], line[1]["base"], len(res)) for line in res
         ]
         return res
+
+    # Check that only one sale channel is selected
+    @api.constrains("agency_id", "channel_type_id")
+    def _check_only_one_channel(self):
+        for record in self:
+            if record.agency_id and record.channel_type_id:
+                raise models.ValidationError(_("There must be only one sale channel"))

pms/views/res_partner_views.xml

@@ -40,7 +40,9 @@
                 </button>
             </xpath>
             <xpath expr="//field[@name='name']" position="after">
-                <field name="is_agency" />
+                <group>
+                    <field name="is_agency" />
+                </group>
             </xpath>
             <xpath expr="//page[@name='internal_notes']" position="after">
                 <page