diff --git a/addons/project/models/project.py b/addons/project/models/project.py
index ad874ebfdab..f9a9f53c406 100644
--- a/addons/project/models/project.py
+++ b/addons/project/models/project.py
@@ -408,7 +408,7 @@ class Project(models.Model):
     def _create_analytic_account_from_values(self, values):
         analytic_account = self.env['account.analytic.account'].create({
             'name': values.get('name', _('Unknown Analytic Account')),
-            'company_id': values.get('company_id', self.env.user.company_id.id),
+            'company_id': values.get('company_id') or self.env.company.id,
             'partner_id': values.get('partner_id'),
             'active': True,
         })
@@ -519,9 +519,7 @@ class Task(models.Model):
         string='Customer',
         default=lambda self: self._get_default_partner())
     manager_id = fields.Many2one('res.users', string='Project Manager', related='project_id.user_id', readonly=True, related_sudo=False)
-    company_id = fields.Many2one('res.company',
-        string='Company',
-        default=lambda self: self.env.company)
+    company_id = fields.Many2one('res.company', string='Company', required=True, default=lambda self: self.env.company)
     color = fields.Integer(string='Color Index')
     user_email = fields.Char(related='user_id.email', string='User Email', readonly=True, related_sudo=False)
     attachment_ids = fields.One2many('ir.attachment', compute='_compute_attachment_ids', string="Main Attachments",
diff --git a/addons/project/security/project_security.xml b/addons/project/security/project_security.xml
index c50386bb6ec..eecc68d1ccb 100644
--- a/addons/project/security/project_security.xml
+++ b/addons/project/security/project_security.xml
@@ -38,10 +38,7 @@
         <field name="name">Project: multi-company</field>
         <field name="model_id" ref="model_project_project"/>
         <field name="global" eval="True"/>
-        <field name="domain_force">['|',
-                                        ('company_id', '=', False),
-                                        ('company_id', 'in', company_ids),
-                                    ]</field>
+        <field name="domain_force">[('company_id', 'in', company_ids)]</field>
     </record>
 
     <record model="ir.rule" id="project_project_manager_rule">
@@ -67,10 +64,7 @@
         <field name="name">Project/Task: multi-company</field>
         <field name="model_id" ref="model_project_task"/>
         <field name="global" eval="True"/>
-        <field name="domain_force">['|',
-                                        ('company_id', '=', False),
-                                        ('company_id', 'in', company_ids),
-                                    ]</field>
+        <field name="domain_force">[('company_id', 'in', company_ids)]</field>
     </record>
 
     <record model="ir.rule" id="task_visibility_rule">
@@ -100,7 +94,7 @@
         <field name="name">Task Analysis multi-company</field>
         <field name="model_id" ref="model_report_project_task_user"/>
         <field name="global" eval="True"/>
-        <field name="domain_force">['|',('company_id','=',False),('company_id', 'in', company_ids)]</field>
+        <field name="domain_force">[('company_id', 'in', company_ids)]</field>
     </record>
 
      <!-- Portal -->
diff --git a/addons/project/views/project_views.xml b/addons/project/views/project_views.xml
index 035f70f4e5f..cbd14f7caa1 100644
--- a/addons/project/views/project_views.xml
+++ b/addons/project/views/project_views.xml
@@ -151,15 +151,12 @@
                                     <field name="rating_status_period"  class="oe_inline" attrs="{'required': [('rating_status','=','periodic')], 'invisible': [('rating_status','!=','periodic')]}" groups="project.group_project_rating"/>
                                     <field name="portal_show_rating" attrs="{'invisible': [('rating_status','==','no')]}" groups="project.group_project_rating"/>
                                     <field name="subtask_project_id" groups="project.group_subtask_project"/>
+                                    <field name="company_id" groups="base.group_multi_company"/>
                                 </group>
                                 <group name="extra_settings">
                                 </group>
                             </group>
                             <group name="misc">
-                                <group string="Configuration" groups="base.group_no_one" name="configuration">
-                                    <field name="sequence" groups="base.group_no_one"/>
-                                    <field name="company_id" groups="base.group_multi_company"/>
-                                </group>
                                 <group string="Time Scheduling">
                                     <field name="resource_calendar_id"/>
                                 </group>
diff --git a/addons/project_timesheet_holidays/models/hr_holidays.py b/addons/project_timesheet_holidays/models/hr_holidays.py
index ada3b56acc1..e78420a0176 100644
--- a/addons/project_timesheet_holidays/models/hr_holidays.py
+++ b/addons/project_timesheet_holidays/models/hr_holidays.py
@@ -83,6 +83,7 @@ class Holidays(models.Model):
                     'date': fields.Date.to_string(day_date),
                     'holiday_id': holiday.id,
                     'employee_id': holiday.employee_id.id,
+                    'company_id': holiday_task.company_id.id or holiday_project.company_id.id,
                 })
 
         return super(Holidays, self)._validate_leave_request()
diff --git a/addons/project_timesheet_holidays/models/res_company.py b/addons/project_timesheet_holidays/models/res_company.py
index 948b4f3bffa..56b59e1b022 100644
--- a/addons/project_timesheet_holidays/models/res_company.py
+++ b/addons/project_timesheet_holidays/models/res_company.py
@@ -2,6 +2,7 @@
 # Part of Odoo. See LICENSE file for full copyright and licensing details.
 
 from odoo import api, fields, models, _
+from odoo.exceptions import ValidationError
 
 
 class Company(models.Model):
@@ -14,6 +15,13 @@ class Company(models.Model):
         'project.task', string="Time Off Task",
         domain="[('project_id', '=', leave_timesheet_project_id)]")
 
+    @api.constrains('leave_timesheet_project_id')
+    def _check_leave_timesheet_project_id_company(self):
+        for company in self:
+            if company.leave_timesheet_project_id:
+                if company.leave_timesheet_project_id.company_id != company:
+                    raise ValidationError(_('The Internal Project of a company should be in that company.'))
+
     def init(self):
         self.search([('leave_timesheet_project_id', '=', False)])._create_leave_project_task()
 
@@ -40,7 +48,7 @@ class Company(models.Model):
                     'name': _('Time Off'),
                     'project_id': company.leave_timesheet_project_id.id,
                     'active': False,
-                    'company_id': False,
+                    'company_id': company.id,
                 })
                 company.write({
                     'leave_timesheet_task_id': task.id,
diff --git a/addons/project_timesheet_holidays/models/res_config_settings.py b/addons/project_timesheet_holidays/models/res_config_settings.py
index bbc0b0a12ce..2bf86555488 100644
--- a/addons/project_timesheet_holidays/models/res_config_settings.py
+++ b/addons/project_timesheet_holidays/models/res_config_settings.py
@@ -7,5 +7,5 @@ from odoo import fields, models
 class ResConfigSettings(models.TransientModel):
     _inherit = 'res.config.settings'
 
-    leave_timesheet_project_id = fields.Many2one(related='company_id.leave_timesheet_project_id', string="Internal Project", readonly=False)
-    leave_timesheet_task_id = fields.Many2one(related='company_id.leave_timesheet_task_id', string="Time Off Task", readonly=False)
+    leave_timesheet_project_id = fields.Many2one(related='company_id.leave_timesheet_project_id', string="Internal Project", domain="[('company_id', '=', company_id)]", readonly=False)
+    leave_timesheet_task_id = fields.Many2one(related='company_id.leave_timesheet_task_id', string="Time Off Task", domain="[('company_id', '=', company_id)]", readonly=False)
diff --git a/addons/sale/models/sale.py b/addons/sale/models/sale.py
index 4e197509019..aa770884e07 100644
--- a/addons/sale/models/sale.py
+++ b/addons/sale/models/sale.py
@@ -174,7 +174,7 @@ class SaleOrder(models.Model):
 
     payment_term_id = fields.Many2one('account.payment.term', string='Payment Terms', oldname='payment_term', help="Payment terms applies to all invoices issued from this order.")
     fiscal_position_id = fields.Many2one('account.fiscal.position', oldname='fiscal_position', string='Fiscal Position', help=" Fiscal positions are used to adapt taxes and accounts for particular customers or sales orders/invoices. The default value comes from the customer.")
-    company_id = fields.Many2one('res.company', 'Company', default=lambda self: self.env.company)
+    company_id = fields.Many2one('res.company', 'Company', required=True, default=lambda self: self.env.company)
     team_id = fields.Many2one('crm.team', 'Sales Team', change_default=True, default=_get_default_team, oldname='section_id')
 
     signature = fields.Binary('Signature', help='Signature received through the portal.', copy=False, attachment=True)
diff --git a/addons/sale/security/sale_security.xml b/addons/sale/security/sale_security.xml
index 129046dac20..44fe53fa1e8 100644
--- a/addons/sale/security/sale_security.xml
+++ b/addons/sale/security/sale_security.xml
@@ -42,14 +42,14 @@
         <field name="name">Sales Order multi-company</field>
         <field name="model_id" ref="model_sale_order"/>
         <field name="global" eval="True"/>
-        <field name="domain_force">['|',('company_id','=',False),('company_id', 'in', company_ids)]</field>
+        <field name="domain_force">[('company_id', 'in', company_ids)]</field>
     </record>
 
     <record model="ir.rule" id="sale_order_line_comp_rule">
         <field name="name">Sales Order Line multi-company</field>
         <field name="model_id" ref="model_sale_order_line"/>
         <field name="global" eval="True"/>
-        <field name="domain_force">['|',('company_id','=',False),('company_id', 'in', company_ids)]</field>
+        <field name="domain_force">['|', ('company_id', '=', False), ('company_id', 'in', company_ids)]</field>
     </record>
 
     <record model="ir.rule" id="sale_order_report_comp_rule">
diff --git a/addons/sale_timesheet/models/sale_order.py b/addons/sale_timesheet/models/sale_order.py
index dd903ba7330..70c45218e9b 100644
--- a/addons/sale_timesheet/models/sale_order.py
+++ b/addons/sale_timesheet/models/sale_order.py
@@ -212,7 +212,7 @@ class SaleOrderLine(models.Model):
         if 'product_uom_qty' in values:
             for line in self:
                 if line.task_id:
-                    planned_hours = line._convert_qty_company_hours()
+                    planned_hours = line._convert_qty_company_hours(line.task_id.company_id)
                     line.task_id.write({'planned_hours': planned_hours})
         return result
 
@@ -220,8 +220,8 @@ class SaleOrderLine(models.Model):
     # Service : Project and task generation
     ###########################################
 
-    def _convert_qty_company_hours(self):
-        company_time_uom_id = self.env.company.project_time_mode_id
+    def _convert_qty_company_hours(self, dest_company):
+        company_time_uom_id = dest_company.project_time_mode_id
         if self.product_uom.id != company_time_uom_id.id and self.product_uom.category_id.id == company_time_uom_id.category_id.id:
             planned_hours = self.product_uom._compute_quantity(self.product_uom_qty, company_time_uom_id)
         else:
@@ -249,6 +249,7 @@ class SaleOrderLine(models.Model):
             'sale_line_id': self.id,
             'sale_order_id': self.order_id.id,
             'active': True,
+            'company_id': self.company_id.id,
         }
         if self.product_id.project_template_id:
             values['name'] = "%s - %s" % (values['name'], self.product_id.project_template_id.name)
@@ -270,7 +271,7 @@ class SaleOrderLine(models.Model):
 
     def _timesheet_create_task_prepare_values(self, project):
         self.ensure_one()
-        planned_hours = self._convert_qty_company_hours()
+        planned_hours = self._convert_qty_company_hours(self.company_id)
         sale_line_name_parts = self.name.split('\n')
         title = sale_line_name_parts[0] or self.product_id.name
         description = '<br/>'.join(sale_line_name_parts[1:])
diff --git a/addons/sale_timesheet/wizard/project_create_sale_order.py b/addons/sale_timesheet/wizard/project_create_sale_order.py
index 11c473517b1..364e3056ac3 100644
--- a/addons/sale_timesheet/wizard/project_create_sale_order.py
+++ b/addons/sale_timesheet/wizard/project_create_sale_order.py
@@ -76,6 +76,7 @@ class ProjectCreateSalesOrder(models.TransientModel):
             'partner_id': self.partner_id.id,
             'analytic_account_id': self.project_id.analytic_account_id.id,
             'client_order_ref': self.project_id.name,
+            'company_id': self.project_id.company_id.id,
         })
         sale_order.onchange_partner_id()
         sale_order.onchange_partner_shipping_id()