diff --git a/lib/OpenLayers/Layer/Vector.js b/lib/OpenLayers/Layer/Vector.js
index 79e7c7d050..e394c0a660 100644
--- a/lib/OpenLayers/Layer/Vector.js
+++ b/lib/OpenLayers/Layer/Vector.js
@@ -479,12 +479,13 @@ OpenLayers.Layer.Vector = OpenLayers.Class(OpenLayers.Layer, {
             if (!dragging) {
                 this.renderer.root.style.visibility = 'hidden';
 
-                var viewPortWidth = this.map.viewPortDiv.clientWidth; 
-                var viewPortHeight = this.map.viewPortDiv.clientHeight; 
-                var offsetLeft = (viewPortWidth / 2 * this.ratio) - viewPortWidth / 2;
+                var viewSize = this.map.getSize(),
+                    viewWidth = viewSize.w,
+                    viewHeight = viewSize.h,
+                    offsetLeft = (viewWidth / 2 * this.ratio) - viewWidth / 2,
+                    offsetTop = (viewHeight / 2 * this.ratio) - viewHeight / 2;
                 offsetLeft += parseInt(this.map.layerContainerDiv.style.left, 10);
                 offsetLeft = -Math.round(offsetLeft);
-                var offsetTop = (viewPortHeight / 2 * this.ratio) - viewPortHeight / 2;
                 offsetTop += parseInt(this.map.layerContainerDiv.style.top, 10);
                 offsetTop = -Math.round(offsetTop);