diff --git a/wp-content/themes/twentytwelve/editor-style.css b/wp-content/themes/twentytwelve/editor-style.css
index f376dc7900..24e9b24f63 100644
--- a/wp-content/themes/twentytwelve/editor-style.css
+++ b/wp-content/themes/twentytwelve/editor-style.css
@@ -308,7 +308,7 @@ img[class*="wp-image-"],
 img[class*="attachment-"] {
 	height: auto; /* Make sure images with WordPress-added height and width attributes are scaled correctly */
 }
-img.mceWPnextpage {
+img.mce-wp-nextpage {
 	border-radius: 0;
 	box-shadow: none;
 }
@@ -339,4 +339,4 @@ img.wp-smiley {
 	line-height: 2;
 	margin: 0 0 24px;
 	margin: 0 0 1.71429rem;
-}
\ No newline at end of file
+}