Ticket #41230: 41230.patch

src/wp-includes/js/tinymce/plugins/wordpress/plugin.js

@@ -187 +187 @@
                 var parent, html, title,
                         classname = 'wp-more-tag',
                         dom = editor.dom,
-                        node = editor.selection.getNode();
+                        node = editor.selection.getNode(),
+                        rootNode = editor.getBody();
 
                 tag = tag || 'more';
                 classname += ' mce-wp-' + tag;
@@ -197 +198 @@
                         'data-wp-more="' + tag + '" data-mce-resize="false" data-mce-placeholder="1" />';
 
                 // Most common case
-                if ( node.nodeName === 'BODY' || ( node.nodeName === 'P' && node.parentNode.nodeName === 'BODY' ) ) {
+                if ( node === rootNode || ( node.nodeName === 'P' && node.parentNode === rootNode ) ) {
                         editor.insertContent( html );
                         return;
                 }
 
                 // Get the top level parent node
                 parent = dom.getParent( node, function( found ) {
-                        if ( found.parentNode && found.parentNode.nodeName === 'BODY' ) {
+                        if ( found.parentNode && found.parentNode === rootNode ) {
                                 return true;
                         }