diff --git a/wagtail/wagtailadmin/static_src/wagtailadmin/scss/core.scss b/wagtail/wagtailadmin/static_src/wagtailadmin/scss/core.scss
index d1c06e972..24acc0994 100644
--- a/wagtail/wagtailadmin/static_src/wagtailadmin/scss/core.scss
+++ b/wagtail/wagtailadmin/static_src/wagtailadmin/scss/core.scss
@@ -139,12 +139,8 @@ footer {
     }
 
     .actions {
+        width: 250px;
         margin-right: $grid-gutter-width / 2;
-        width: auto;
-
-        .dropdown {
-            width: 250px;
-        }
     }
 
     .meta {
@@ -169,12 +165,9 @@ footer {
     }
 
     @media screen and (max-width: $breakpoint-mobile) {
-        .actions {
+        .actions,
+        .preview {
             width: 100%;
-
-            .dropdown {
-                width: 100%;
-            }
         }
 
         .meta p {
diff --git a/wagtail/wagtailadmin/templates/wagtailadmin/pages/create.html b/wagtail/wagtailadmin/templates/wagtailadmin/pages/create.html
index 22e782bef..0c22a292a 100644
--- a/wagtail/wagtailadmin/templates/wagtailadmin/pages/create.html
+++ b/wagtail/wagtailadmin/templates/wagtailadmin/pages/create.html
@@ -41,7 +41,7 @@
                     </div>
                 </li>
 
-                <li class="actions preview">
+                <li class="preview">
                     {% trans 'Preview' as preview_label %}
                     {% if preview_modes|length > 1 %}
                         <div class="dropdown dropup dropdown-button match-width">
diff --git a/wagtail/wagtailadmin/templates/wagtailadmin/pages/edit.html b/wagtail/wagtailadmin/templates/wagtailadmin/pages/edit.html
index c409d59d2..c27731874 100644
--- a/wagtail/wagtailadmin/templates/wagtailadmin/pages/edit.html
+++ b/wagtail/wagtailadmin/templates/wagtailadmin/pages/edit.html
@@ -64,7 +64,7 @@
                     </div>
                 </li>
 
-                <li class="actions preview">
+                <li class="preview">
                     {% trans 'Preview' as preview_label %}
                     {% if preview_modes|length > 1 %}
                         <div class="dropdown dropup dropdown-button match-width">