diff --git a/vector.js b/vector.js
index bf9262326..375581d68 100644
--- a/vector.js
+++ b/vector.js
@@ -9,7 +9,6 @@ $( function () {
 	 */
 	var $cactions = $( '#p-cactions' ),
 		$tabContainer = $( '#p-views ul' ),
-		rAF = window.requestAnimationFrame || setTimeout,
 		// Avoid forced style calculation during page load
 		initialCactionsWidth = function () {
 			var width = $cactions.width();
@@ -19,7 +18,7 @@ $( function () {
 			return width;
 		};
 
-	rAF( initialCactionsWidth );
+	mw.requestIdleCallback( initialCactionsWidth );
 
 	/**
 	 * Focus search input at the very end