diff --git a/lib/OpenLayers/Layer/Grid.js b/lib/OpenLayers/Layer/Grid.js
index 17401946fe..4256bda5cb 100644
--- a/lib/OpenLayers/Layer/Grid.js
+++ b/lib/OpenLayers/Layer/Grid.js
@@ -452,6 +452,7 @@ OpenLayers.Layer.Grid = OpenLayers.Class(OpenLayers.Layer.HTTPRequest, {
         if(this.grid.length > 0) {
             var backBuffer = document.createElement('div');
             backBuffer.id = this.div.id + '_bb';
+            backBuffer.className = 'olBackBuffer';
             backBuffer.style.position = 'absolute';
             backBuffer.style.width = '100%';
             backBuffer.style.height = '100%';