diff --git a/lib/OpenLayers/Control/PanZoomBar.js b/lib/OpenLayers/Control/PanZoomBar.js
index ebce5ad6ac..8debba2319 100644
--- a/lib/OpenLayers/Control/PanZoomBar.js
+++ b/lib/OpenLayers/Control/PanZoomBar.js
@@ -294,8 +294,8 @@ OpenLayers.Control.PanZoomBar = OpenLayers.Class(OpenLayers.Control.PanZoom, {
                 (evt.clientY - offsets[1]) < parseInt(this.zoombarDiv.style.height) - 2) {
                 var newTop = parseInt(this.slider.style.top) - deltaY;
                 this.slider.style.top = newTop+"px";
+                this.mouseDragStart = evt.xy.clone();
             }
-            this.mouseDragStart = evt.xy.clone();
             OpenLayers.Event.stop(evt);
         }
     },