TinyMCE:

- When editing pages, add body class with the page template, or `page-template-default`.
- Change the page template class when the users select another template, similarly to changing the post type class for posts.

Props webmandesign.
Fixes #37599.

git-svn-id: https://develop.svn.wordpress.org/trunk@38803 602fd350-edb4-49c9-b593-d223f7449a82

src/wp-admin/js/post.js

@@ -1167,6 +1167,23 @@ jQuery(document).ready( function($) {
 				$( document ).trigger( 'editor-classchange' );
 			}
 		});
+
+		// When changing page template, change the editor body class
+		$( '#page_template' ).on( 'change.set-editor-class', function() {
+			var editor, body, pageTemplate = $( this ).val() || '';
+
+			pageTemplate = pageTemplate.substr( pageTemplate.lastIndexOf( '/' ) + 1, pageTemplate.length )
+				.replace( /\.php$/, '' )
+				.replace( /\./g, '-' );
+
+			if ( pageTemplate && ( editor = tinymce.get( 'content' ) ) ) {
+				body = editor.getBody();
+				body.className = body.className.replace( /\bpage-template-[^ ]+/, '' );
+				editor.dom.addClass( body, 'page-template-' + pageTemplate );
+				$( document ).trigger( 'editor-classchange' );
+			}
+		});
+
 	}
 
 	// Save on pressing [ctrl]/[command] + [s] in the Text editor.