Index: src/wp-content/themes/twentyfifteen/style.css
===================================================================
--- src/wp-content/themes/twentyfifteen/style.css	(revision 29900)
+++ src/wp-content/themes/twentyfifteen/style.css	(working copy)
@@ -3805,11 +3805,8 @@
 	.sidebar {
 		float: left;
 		height: 100%;
-		overflow-y: auto;
 		margin-right: -100%;
 		max-width: 413px;
-		-webkit-overflow-scrolling: touch;
-		position: fixed;
 		width: 29.4118%;
 	}