Index: /CKEditor/trunk/_source/plugins/liststyle/dialogs/liststyle.js
===================================================================
--- /CKEditor/trunk/_source/plugins/liststyle/dialogs/liststyle.js	(revision 6948)
+++ /CKEditor/trunk/_source/plugins/liststyle/dialogs/liststyle.js	(revision 6949)
@@ -145,5 +145,8 @@
 										{
 											var val = parseInt( this.getValue(), 10 );
-											element.setAttribute( 'start',  isNaN( val ) ? 1 : val  );
+											if ( isNaN( val ) )
+												element.removeAttribute( 'start' );
+											else
+												element.setAttribute( 'start', val );
 										}
 									},