diff --git a/addons/web/static/src/scss/modal.scss b/addons/web/static/src/scss/modal.scss
index 7518fe24ba7df0862af9719ecf140bae3af6be99..892d91cfc508e4ff6d6036608f0c56e3f86fdd39 100644
--- a/addons/web/static/src/scss/modal.scss
+++ b/addons/web/static/src/scss/modal.scss
@@ -18,6 +18,11 @@
                 padding: 0;
             }
 
+            // Fix dropzones of nested sortable.
+            .mjs-nestedSortable-error {
+                outline: none;
+            }
+
             .o_modal_header {
                 @include o-webclient-padding($top: 10px, $bottom: 10px);
                 @include clearfix;