diff --git a/base_global_discount/__manifest__.py b/base_global_discount/__manifest__.py
index 28ae4418..e1cac3dd 100644
--- a/base_global_discount/__manifest__.py
+++ b/base_global_discount/__manifest__.py
@@ -13,8 +13,8 @@
         'product',
     ],
     'data': [
-        'security/ir.model.access.csv',
         'security/security.xml',
+        'security/ir.model.access.csv',
         'views/global_discount_views.xml',
         'views/res_partner_views.xml',
     ],
diff --git a/base_global_discount/migrations/12.0.2.0.0/post_migrate.py b/base_global_discount/migrations/12.0.2.0.0/post_migrate.py
new file mode 100644
index 00000000..141c2f62
--- /dev/null
+++ b/base_global_discount/migrations/12.0.2.0.0/post_migrate.py
@@ -0,0 +1,10 @@
+# Copyright 2020 David Vidal
+# License LGPL-3.0 or later (http://www.gnu.org/licenses/lgpl).
+from openupgradelib.openupgrade import migrate
+
+
+@migrate()
+def migrate(env, version):
+    """Put all partner managers as global discount managers"""
+    users = env.ref("base.group_partner_manager").users
+    env.ref("base_global_discount.group_global_discount").users = users
diff --git a/base_global_discount/models/res_partner.py b/base_global_discount/models/res_partner.py
index 16a25aca..ee9c87a0 100644
--- a/base_global_discount/models/res_partner.py
+++ b/base_global_discount/models/res_partner.py
@@ -20,3 +20,15 @@ class ResPartner(models.Model):
         string='Purchase Global Discounts',
         domain=[('discount_scope', '=', 'purchase')],
     )
+    # HACK: Looks like UI doesn't behave well with Many2many fields and
+    # negative groups when the same field is shown. In this case, we want to
+    # show the readonly version to any not in the global discount group.
+    # TODO: Check if it's fixed in future versions
+    customer_global_discount_ids_readonly = fields.Many2many(
+        related="customer_global_discount_ids",
+        readonly=True,
+    )
+    supplier_global_discount_ids_readonly = fields.Many2many(
+        related="customer_global_discount_ids",
+        readonly=True,
+    )
diff --git a/base_global_discount/readme/CONFIGURE.rst b/base_global_discount/readme/CONFIGURE.rst
index 0e5cea40..bb80f62d 100644
--- a/base_global_discount/readme/CONFIGURE.rst
+++ b/base_global_discount/readme/CONFIGURE.rst
@@ -1,5 +1,6 @@
 To use this module, you need to:
 
+#. Go to *Settings > Users*, choose yours and set *Manage Global Discounts*.
 #. Go to *Settings > Parameters > Global Discounts*
 #. Choose the discount scope (sales or purchases).
 #. You can also restrict it to a certain company if needed.
diff --git a/base_global_discount/readme/USAGE.rst b/base_global_discount/readme/USAGE.rst
index 8d9135e4..0750fc83 100644
--- a/base_global_discount/readme/USAGE.rst
+++ b/base_global_discount/readme/USAGE.rst
@@ -1,4 +1,5 @@
-You can assign global discounts to partners as well:
+You can assign global discounts to partners as well. You'll need the proper
+permission (*Manage Global Discounts*):
 
 #. Go to a partner that is a company.
 #. Go to the *Sales & Purchases* tab.
diff --git a/base_global_discount/security/ir.model.access.csv b/base_global_discount/security/ir.model.access.csv
index 33fcbd8f..e6e0d9fa 100644
--- a/base_global_discount/security/ir.model.access.csv
+++ b/base_global_discount/security/ir.model.access.csv
@@ -1,3 +1,3 @@
 id,name,model_id:id,group_id:id,perm_read,perm_write,perm_create,perm_unlink
 access_global_discount_user,Global Discount Users,model_global_discount,base.group_user,1,0,0,0
-access_global_discount_partner_manager,Global Discount Partner Manager,model_global_discount,base.group_partner_manager,1,1,1,1
+access_global_discount_manager,Global Discount Manager,model_global_discount,base_global_discount.group_global_discount,1,1,1,1
diff --git a/base_global_discount/security/security.xml b/base_global_discount/security/security.xml
index 7adb4ae9..42fd4950 100644
--- a/base_global_discount/security/security.xml
+++ b/base_global_discount/security/security.xml
@@ -12,5 +12,8 @@
         <field name="perm_write" eval="1"/>
         <field name="perm_unlink" eval="1"/>
     </record>
-
+    <record id="group_global_discount" model="res.groups">
+        <field name="name">Manage Global Discounts</field>
+        <field name="category_id" ref="base.module_category_hidden"/>
+    </record>
 </odoo>
diff --git a/base_global_discount/views/global_discount_views.xml b/base_global_discount/views/global_discount_views.xml
index 3023274e..4a293a51 100644
--- a/base_global_discount/views/global_discount_views.xml
+++ b/base_global_discount/views/global_discount_views.xml
@@ -41,9 +41,12 @@
         <field name="view_mode">tree,form</field>
     </record>
 
-    <menuitem id="menu_global_discount"
+    <menuitem 
+        id="menu_global_discount"
         action="action_global_discount_tree"
         name="Global Discounts"
-        sequence="1" parent="base.menu_ir_property"/>
+        sequence="1" parent="base.menu_ir_property"
+        groups="base_global_discount.group_global_discount"
+    />
 
 </odoo>
diff --git a/base_global_discount/views/res_partner_views.xml b/base_global_discount/views/res_partner_views.xml
index be4aae3a..ec40ca40 100644
--- a/base_global_discount/views/res_partner_views.xml
+++ b/base_global_discount/views/res_partner_views.xml
@@ -8,11 +8,16 @@
          <field name="inherit_id" ref="base.view_partner_form"/>
          <field name="arch" type="xml">
             <group name="sale" position="inside">
-                <field name="customer_global_discount_ids" widget="many2many_tags"
+                <field name="customer_global_discount_ids" widget="many2many_tags" groups="base_global_discount.group_global_discount"
+                       attrs="{'invisible': [('customer', '=', False), ('is_company', '=', False), ('parent_id', '!=', False)]}"/>
+                <field name="customer_global_discount_ids_readonly" widget="many2many_tags"
+                       groups="!base_global_discount.group_global_discount"
                        attrs="{'invisible': [('customer', '=', False), ('is_company', '=', False), ('parent_id', '!=', False)]}"/>
             </group>
             <group name="purchase" position="inside">
-                <field name="supplier_global_discount_ids" widget="many2many_tags"
+                <field name="supplier_global_discount_ids" widget="many2many_tags" groups="base_global_discount.group_global_discount"
+                       attrs="{'invisible': [('supplier', '=', False), ('is_company', '=', False), ('parent_id', '!=', False)]}"/>
+                <field name="supplier_global_discount_ids" widget="many2many_tags" groups="!base_global_discount.group_global_discount"
                        attrs="{'invisible': [('supplier', '=', False), ('is_company', '=', False), ('parent_id', '!=', False)]}"/>
             </group>
          </field>