diff --git a/addons/mail/static/src/scss/discuss.scss b/addons/mail/static/src/scss/discuss.scss
index 8d328b028bf..d6f0ec10760 100644
--- a/addons/mail/static/src/scss/discuss.scss
+++ b/addons/mail/static/src/scss/discuss.scss
@@ -252,7 +252,8 @@
         }
 
         .o_mail_discuss_content {
-            flex: 1 0 0;
+            flex: 1 1 auto;
+            min-height: 0;
             margin-left: 10px;
             margin-right: 10px;
             background-color: transparent;