diff --git a/addons/mail/models/mail_render_mixin.py b/addons/mail/models/mail_render_mixin.py
index 7476becde46..27b7613669f 100644
--- a/addons/mail/models/mail_render_mixin.py
+++ b/addons/mail/models/mail_render_mixin.py
@@ -14,7 +14,7 @@ from werkzeug import urls
 
 from odoo import _, api, fields, models, tools
 from odoo.exceptions import UserError
-from odoo.tools import safe_eval
+from odoo.tools import is_html_empty, safe_eval
 
 _logger = logging.getLogger(__name__)
 
@@ -279,6 +279,7 @@ class MailRenderMixin(models.AbstractModel):
             'format_duration': lambda value: tools.format_duration(value),
             'user': self.env.user,
             'ctx': self._context,
+            'is_html_empty': is_html_empty,
         }
 
     @api.model
diff --git a/addons/portal/models/ir_ui_view.py b/addons/portal/models/ir_ui_view.py
index ca4051755f7..64a63bfee0d 100644
--- a/addons/portal/models/ir_ui_view.py
+++ b/addons/portal/models/ir_ui_view.py
@@ -4,6 +4,7 @@
 from odoo import api, models, fields
 from odoo.http import request
 from odoo.addons.http_routing.models.ir_http import url_for
+from odoo.tools import is_html_empty
 
 
 class View(models.Model):
@@ -24,5 +25,6 @@ class View(models.Model):
                 self._context.copy(),
                 languages=[lang for lang in Lang.get_available() if lang[0] in portal_lang_code],
                 url_for=url_for,
+                is_html_empty=is_html_empty,
             ))
         return qcontext
diff --git a/odoo/addons/base/models/ir_actions_report.py b/odoo/addons/base/models/ir_actions_report.py
index 9eaeb72bfb9..c00b41e6b72 100644
--- a/odoo/addons/base/models/ir_actions_report.py
+++ b/odoo/addons/base/models/ir_actions_report.py
@@ -6,7 +6,7 @@ from odoo import api, fields, models, tools, SUPERUSER_ID, _
 from odoo.exceptions import UserError, AccessError
 from odoo.tools.safe_eval import safe_eval, time
 from odoo.tools.misc import find_in_path
-from odoo.tools import config
+from odoo.tools import config, is_html_empty
 from odoo.sql_db import TestCursor
 from odoo.http import request
 from odoo.osv.expression import NEGATIVE_TERM_OPERATORS, FALSE_DOMAIN
@@ -886,6 +886,7 @@ class IrActionsReport(models.Model):
                 'doc_model': self_sudo.model,
                 'docs': docs,
             })
+        data['is_html_empty'] = is_html_empty
         return data
 
     def _render(self, res_ids, data=None):
diff --git a/odoo/addons/base/tests/test_mail.py b/odoo/addons/base/tests/test_mail.py
index ff92a840a2b..755b959f573 100644
--- a/odoo/addons/base/tests/test_mail.py
+++ b/odoo/addons/base/tests/test_mail.py
@@ -329,7 +329,7 @@ class TestHtmlTools(BaseCase):
             self.assertTrue(is_html_empty(content))
 
         void_html_samples = ['<p><br></p>', '<p><br> </p>', '<p><br /></p >', '<p style="margin: 4px"></p>',
-                             '<div style="margin: 4px"></div>']
+                             '<div style="margin: 4px"></div>', '<p class="oe_testing"><br></p>']
         for content in void_html_samples:
             self.assertTrue(is_html_empty(content), 'Failed with %s' % content)
 
diff --git a/odoo/tools/mail.py b/odoo/tools/mail.py
index bfbfddea275..0dc0bf658e5 100644
--- a/odoo/tools/mail.py
+++ b/odoo/tools/mail.py
@@ -279,7 +279,7 @@ def is_html_empty(html_content):
     """
     if not html_content:
         return True
-    tag_re = re.compile(r'\<\s*\/?(?:p|div|span|br|b|i)\s*(?:style=\".+\")?/?\s*\>')
+    tag_re = re.compile(r'\<\s*\/?(?:p|div|span|br|b|i)(?:(?=\s+\w*)[^/>]*|\s*)/?\s*\>')
     return not bool(re.sub(tag_re, '', html_content).strip())