When moving by long distances (whole screenfuls) via API setCenter calls, reinitialize the grid. This solves an 'infinite loop' like problem where if you jumped by a long way, where addColumn/addRow were simply looping for so long that the browser went unresponsive/broken. Fixes issue reported by NickH on users list as well.

git-svn-id: http://svn.openlayers.org/trunk/openlayers@593 dc9f47b5-9b13-0410-9fdd-eb0c1a62fdaf

lib/OpenLayers/Layer/Grid.js

@@ -65,7 +65,13 @@ OpenLayers.Layer.Grid.prototype = Object.extend( new OpenLayers.Layer(), {
         }
         if (!this.grid || zoomChanged) {
             this._initTiles();
-        } else { 
+        } else if ( bounds.top > this.getGridBounds().bottom ||
+                    bounds.left > this.getGridBounds().right ||
+                    bounds.right < this.getGridBounds().left ||
+                    bounds.bottom < this.getGridBounds().top  ) {
+            this._initTiles();
+        
+        } else {
             var i = 0;
             while (this.getGridBounds().bottom > bounds.bottom) {
                this.insertRow(false);