Index: /CKEditor/trunk/_source/core/dom/node.js
===================================================================
--- /CKEditor/trunk/_source/core/dom/node.js	(revision 7456)
+++ /CKEditor/trunk/_source/core/dom/node.js	(revision 7457)
@@ -345,5 +345,8 @@
 			{
 				previous = previous.previousSibling;
-				retval = previous && new CKEDITOR.dom.node( previous );
+
+				// Avoid returning the doc type node.
+				// http://www.w3.org/TR/REC-DOM-Level-1/level-one-core.html#ID-412266927
+				retval = previous && previous.nodeType != 10 && new CKEDITOR.dom.node( previous );
 			}
 			while ( retval && evaluator && !evaluator( retval ) )