Ticket #5162: 5162_2.patch

_source/plugins/undo/plugin.js

@@ -120 +120 @@
         // Gets a snapshot image which represent the current document status.
         function Image( editor )
         {
-                var selection = editor.getSelection();
+                var selection = editor.getSelection(),
+                        contents = this.contents = editor.getSnapshot();
 
-                this.contents   = editor.getSnapshot();
                 this.bookmarks  = selection && selection.createBookmarks2( true );
 
                 // In IE, we need to remove the expando attributes.
-                if ( CKEDITOR.env.ie )
-                        this.contents = this.contents.replace( /\s+_cke_expando=".*?"/g, '' );
+                if ( CKEDITOR.env.ie && contents )
+                        this.contents = contents.replace( /\s+_cke_expando=".*?"/g, '' );
         }
 
         // Attributes that browser may changing them when setting via innerHTML.
@@ -351 +351 @@
                         if ( !image )
                                 image = new Image( this.editor );
 
+                        // Do nothing if it was not possible to retrieve an image.
+                        if ( image.contents === false )
+                                return;
+
                         // Check if this is a duplicate. In such case, do nothing.
                         if ( this.currentImage && image.equals( this.currentImage, onContentOnly ) )
                                 return false;