From 8df1ae0e092079df5bd68bdf712471d729c7d580 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?=C3=89ric=20Lemoine?= <eric.lemoine@gmail.com>
Date: Sat, 29 Oct 2011 21:10:23 +0200
Subject: [PATCH] comparing backBufferData.resolution and serverResolution to
 know if backbuffering should be applied is wrong

---
 lib/OpenLayers/Layer/Grid.js | 13 +++++--------
 1 file changed, 5 insertions(+), 8 deletions(-)

diff --git a/lib/OpenLayers/Layer/Grid.js b/lib/OpenLayers/Layer/Grid.js
index eba00f5e4d..df9bafe49e 100644
--- a/lib/OpenLayers/Layer/Grid.js
+++ b/lib/OpenLayers/Layer/Grid.js
@@ -285,14 +285,12 @@ OpenLayers.Layer.Grid = OpenLayers.Class(OpenLayers.Layer.HTTPRequest, {
                     // an ill-positioned image will be visible during the zoom
                     // transition.
 
-                    if(lastResolution !== serverResolution &&
-                               this.transitionEffect !== 'resize') {
+                    if(zoomChanged && this.transitionEffect !== 'resize') {
                         this.removeBackBuffer();
                     }
 
-                    if(lastResolution === serverResolution ||
-                       (lastResolution &&
-                        this.transitionEffect === 'resize')) {
+                    if(!zoomChanged || (lastResolution &&
+                                        this.transitionEffect === 'resize')) {
                         this.applyBackBuffer(serverResolution);
                     }
 
@@ -325,9 +323,8 @@ OpenLayers.Layer.Grid = OpenLayers.Class(OpenLayers.Layer.HTTPRequest, {
                 }
 
                 if(forceReTile) {
-                    if(this.transitionEffect === 'resize' &&
-                       (lastResolution &&
-                        (lastResolution !== serverResolution))) {
+                    if(zoomChanged && this.transitionEffect === 'resize' &&
+                       lastResolution) {
                         this.applyBackBuffer(serverResolution);
                     }
                     this.initGriddedTiles(bounds);