diff --git a/Resources/views/Event/show.html.twig b/Resources/views/Event/show.html.twig
index af881fbcc..1891fc0c1 100644
--- a/Resources/views/Event/show.html.twig
+++ b/Resources/views/Event/show.html.twig
@@ -127,6 +127,7 @@
             padding: .375rem 1.75rem .375rem .75rem;
             background: url("data:image/svg+xml,%3csvg xmlns='http://www.w3.org/2000/svg' viewBox='0 0 4 5'%3e%3cpath fill='%23343a40' d='M2 0L0 2h4zm0 5L0 3h4z'/%3e%3c/svg%3e")
                 no-repeat right .75rem center/8px 10px;
+            background-color: white;
             border-radius: .25rem;
             -webkit-appearance: none; -moz-appearance: none; appearance: none;
         }
@@ -164,7 +165,7 @@
             <div class="input-group">
                 {{ form_widget(form_add_participation_by_person.person_id, { 'attr' : {
                     'class' : 'custom-select',
-                    'style': 'min-width: 15em; max-width: 20em; display: inline-block;'
+                    'style': 'min-width: 15em; max-width: 18em; display: inline-block;'
                 }} ) }}
                 <div class="input-group-append">
                     {{ form_widget(form_add_participation_by_person.submit, { 'attr' : { 'class' : 'sc-button bt-create' } } ) }}