Index: src/wp-admin/css/customize-nav-menus.css
===================================================================
--- src/wp-admin/css/customize-nav-menus.css	(revision 34010)
+++ src/wp-admin/css/customize-nav-menus.css	(working copy)
@@ -99,7 +99,6 @@
 .customize-control-nav_menu .reorder,
 .reordering .customize-control-nav_menu .reorder-done {
 	display: inline-block;
-	padding: 5px 8px;
 }
 
 .menu-item-reorder-nav {
Index: src/wp-includes/class-wp-customize-control.php
===================================================================
--- src/wp-includes/class-wp-customize-control.php	(revision 34010)
+++ src/wp-includes/class-wp-customize-control.php	(working copy)
@@ -1461,7 +1461,7 @@
 			<?php _e( 'Add a Widget' ); ?>
 		</span>
 
-		<span class="reorder-toggle" tabindex="0">
+		<span class="button reorder-toggle" tabindex="0">
 			<span class="reorder"><?php _ex( 'Reorder', 'Reorder widgets in Customizer' ); ?></span>
 			<span class="reorder-done"><?php _ex( 'Done', 'Cancel reordering widgets in Customizer' ); ?></span>
 		</span>
@@ -1574,7 +1574,7 @@
 		<button type="button" class="button-secondary add-new-menu-item" aria-label="<?php esc_attr_e( 'Add or remove menu items' ); ?>" aria-expanded="false" aria-controls="available-menu-items">
 			<?php _e( 'Add Items' ); ?>
 		</button>
-		<button type="button" class="not-a-button reorder-toggle" aria-label="<?php esc_attr_e( 'Reorder menu items' ); ?>" aria-describedby="reorder-items-desc-{{ data.menu_id }}">
+		<button type="button" class="button reorder-toggle" aria-label="<?php esc_attr_e( 'Reorder menu items' ); ?>" aria-describedby="reorder-items-desc-{{ data.menu_id }}">
 			<span class="reorder"><?php _ex( 'Reorder', 'Reorder menu items in Customizer' ); ?></span>
 			<span class="reorder-done"><?php _ex( 'Done', 'Cancel reordering menu items in Customizer' ); ?></span>
 		</button>