Index: src/js/media/views/attachments/browser.js
===================================================================
--- src/js/media/views/attachments/browser.js	(revision 45497)
+++ src/js/media/views/attachments/browser.js	(working copy)
@@ -470,7 +470,7 @@
 		}
 
 		// Show the sidebar on mobile
-		if ( this.model.id === 'insert' ) {
+		if ( this.model.id === 'insert' || this.model.id === 'library' ) {
 			sidebar.$el.addClass( 'visible' );
 		}
 	},