diff --git a/lib/OpenLayers/Layer/Grid.js b/lib/OpenLayers/Layer/Grid.js
index 880f070acd..5cc262f270 100644
--- a/lib/OpenLayers/Layer/Grid.js
+++ b/lib/OpenLayers/Layer/Grid.js
@@ -351,6 +351,20 @@ OpenLayers.Layer.Grid.prototype =
         // Should be implemented by subclasses
     },
 
+    /**
+     * Once params have been changed, we will need to re-init our tiles
+     *
+     * @param {Object} newParams Hashtable of new params to use
+     */
+    mergeNewParams:function(newArguments) {
+        OpenLayers.Layer.HTTPRequest.prototype.mergeNewParams.apply(this,
+                                                                [newArguments]);
+
+        if (this.map != null) {
+            this._initTiles();
+        }
+    },
+
     
     /** go through and remove all tiles from the grid, calling
      *    destroy() on each of them to kill circular references
diff --git a/lib/OpenLayers/Layer/WMS.js b/lib/OpenLayers/Layer/WMS.js
index 68a7827bd6..91126df6ed 100644
--- a/lib/OpenLayers/Layer/WMS.js
+++ b/lib/OpenLayers/Layer/WMS.js
@@ -126,10 +126,6 @@ OpenLayers.Layer.WMS.prototype =
         var newArguments = [upperParams];
         OpenLayers.Layer.Grid.prototype.mergeNewParams.apply(this, 
                                                              newArguments);
-
-        if (this.map != null) {
-            this._initTiles();
-        }
     },
 
     /** combine the layer's url with its params and these newParams. 
diff --git a/tests/test_Layer_KaMap.html b/tests/test_Layer_KaMap.html
index 4638b17a3b..570209fe33 100644
--- a/tests/test_Layer_KaMap.html
+++ b/tests/test_Layer_KaMap.html
@@ -101,6 +101,31 @@
 
         t.eq( zoom, 2, "getZoomForExtent() returns correct value");
     }   
+    
+    function test_06_Layer_kaMap_mergeNewParams (t) {
+        t.plan( 5 );
+
+        var map = new OpenLayers.Map("map");
+        var url = "http://octo.metacarta.com/cgi-bin/mapserv";
+        layer = new OpenLayers.Layer.KaMap(name, url, params);
+        
+        var newParams = { layers: 'sooper', 
+                          chickpeas: 'image/png'};
+
+        map.addLayer(layer);
+        map.zoomToMaxExtent();
+        t.ok( !layer.grid[0][0].url.match("chickpeas"), "chickpeas is not in URL of first tile in grid" );
+
+        layer.mergeNewParams(newParams);
+        
+        t.eq( layer.params.layers, "sooper", "mergeNewParams() overwrites well");
+        t.eq( layer.params.chickpeas, "image/png", "mergeNewParams() adds well");
+        t.ok( layer.grid[0][0].url.match("chickpeas"), "CHICKPEAS is in URL of first tile in grid" );
+
+        newParams.chickpeas = 151;
+
+        t.eq( layer.params.chickpeas, "image/png", "mergeNewParams() makes clean copy of hashtable");
+    }
 
 
     /** THIS WOULD BE WHERE THE TESTS WOULD GO FOR 
diff --git a/tests/test_Layer_WMS.html b/tests/test_Layer_WMS.html
index 0cefe1558b..744507b98a 100644
--- a/tests/test_Layer_WMS.html
+++ b/tests/test_Layer_WMS.html
@@ -120,18 +120,24 @@
     }
 
     function test_06_Layer_WMS_mergeNewParams (t) {
-        t.plan( 3 );
+        t.plan( 5 );
 
+        var map = new OpenLayers.Map("map");
         var url = "http://octo.metacarta.com/cgi-bin/mapserv";
         layer = new OpenLayers.Layer.WMS(name, url, params);
         
         var newParams = { layers: 'sooper', 
                           chickpeas: 'image/png'};
 
+        map.addLayer(layer);
+        map.zoomToMaxExtent();
+        t.ok( !layer.grid[0][0].url.match("CHICKPEAS"), "CHICKPEAS is not in URL of first tile in grid" );
+
         layer.mergeNewParams(newParams);
         
         t.eq( layer.params.LAYERS, "sooper", "mergeNewParams() overwrites well");
         t.eq( layer.params.CHICKPEAS, "image/png", "mergeNewParams() adds well");
+        t.ok( layer.grid[0][0].url.match("CHICKPEAS"), "CHICKPEAS is in URL of first tile in grid" );
 
         newParams.CHICKPEAS = 151;