Index: _source/plugins/indent/plugin.js
===================================================================
--- _source/plugins/indent/plugin.js	(revision 3391)
+++ _source/plugins/indent/plugin.js	(working copy)
@@ -235,9 +235,12 @@
 			var bookmarks = selection.createBookmarks( true ),
 				nearestListBlock = range.getCommonAncestor();
 
-			while ( !( nearestListBlock.type == CKEDITOR.NODE_ELEMENT && 
-				listNodeNames[ nearestListBlock.getName() ] ) )
+			while ( nearestListBlock )
+			{
+				if ( nearestListBlock.type == CKEDITOR.NODE_ELEMENT && listNodeNames[ nearestListBlock.getName() ] )
+					break;
 				nearestListBlock = nearestListBlock.getParent();
+			}
 
 			if ( nearestListBlock )
 				indentList.call( this, editor, range, nearestListBlock );