Index: src/wp-admin/js/post.js
===================================================================
--- src/wp-admin/js/post.js	(revision 33344)
+++ src/wp-admin/js/post.js	(working copy)
@@ -649,8 +649,9 @@
 
 		$timestampdiv.siblings('a.edit-timestamp').click( function( event ) {
 			if ( $timestampdiv.is( ':hidden' ) ) {
-				$timestampdiv.slideDown('fast');
-				$('#mm').focus();
+				$timestampdiv.slideDown( 'fast', function() {
+					$( 'input, select', $timestampdiv.find( '.timestamp-wrap' ) ).first().focus();
+				} );
 				$(this).hide();
 			}
 			event.preventDefault();