diff --git a/externs/olx.js b/externs/olx.js
index 1096b44768..2165836267 100644
--- a/externs/olx.js
+++ b/externs/olx.js
@@ -4335,7 +4335,7 @@ olx.layer.VectorOptions.prototype.source;
 
 /**
  * Declutter images and text. Decluttering is applied to all image and text
- * styles, and the priority is defined by the z-index of the style. Higher
+ * styles, and the priority is defined by the z-index of the style. Lower
  * z-index means higher priority. Default is `false`.
  * @type {boolean|undefined}
  * @api
@@ -4513,7 +4513,7 @@ olx.layer.VectorTileOptions.prototype.source;
 
 /**
  * Declutter images and text. Decluttering is applied to all image and text
- * styles, and the priority is defined by the z-index of the style. Higher
+ * styles, and the priority is defined by the z-index of the style. Lower
  * z-index means higher priority. When set to `true`, a `renderMode` of
  * `'image'` will be overridden with `'hybrid'`. Default is `false`.
  * @type {boolean|undefined}
diff --git a/src/ol/render/canvas/replaygroup.js b/src/ol/render/canvas/replaygroup.js
index 92cc0f595c..f811872488 100644
--- a/src/ol/render/canvas/replaygroup.js
+++ b/src/ol/render/canvas/replaygroup.js
@@ -187,7 +187,7 @@ ol.render.canvas.ReplayGroup.getCircleArray_ = function(radius) {
 
 ol.render.canvas.ReplayGroup.replayDeclutter = function(declutterReplays, context, rotation) {
   var zs = Object.keys(declutterReplays).map(Number).sort(ol.array.numberSafeCompareFunction);
-  for (var z = zs.length - 1; z >= 0; --z) {
+  for (var z = 0, zz = zs.length; z < zz; ++z) {
     var replayData = declutterReplays[zs[z].toString()];
     for (var i = 0, ii = replayData.length; i < ii;) {
       var replay = replayData[i++];