Index: /CKEditor/trunk/_source/plugins/enterkey/plugin.js
===================================================================
--- /CKEditor/trunk/_source/plugins/enterkey/plugin.js	(revision 3388)
+++ /CKEditor/trunk/_source/plugins/enterkey/plugin.js	(revision 3389)
@@ -42,4 +42,5 @@
 		setTimeout( function()
 			{
+				editor.fire( 'saveSnapshot' );	// Save undo step.
 				if ( mode == CKEDITOR.ENTER_BR || editor.getSelection().getStartElement().hasAscendant( 'pre', true ) )
 					enterBr( editor, mode );