Lightbox = function(grid, toolbar, complete) {
        var self = this;
        this.grid = grid;
-       this.lastSlide = this.grid.children[this.grid.children.length-1];
+       this.slides = [];
+       var node, i;
+       for (i=0 ; i<this.grid.childNodes.length ; i++) {
+               node = this.grid.childNodes[i];
+               if (node.nodeType === 1) { // is element
+                       this.slides.push(node);
+               }
+       }
+       this.lastSlide = this.slides[this.slides.length-1];
        this.fetchingDisabled = false;
        this.complete = complete;
        console.log('complete:', complete)
        
        var url = absolute_url() +
                          '/portfolio_thumbnails_tail?start:int=0&size:int=' +
-                         this.grid.children.length;
+                         this.slides.length;
        req.open('GET', url, true);
        req.send();
 };
 
 Lightbox.prototype._refreshGrid = function(req) {
        var doc = req.responseXML.documentElement;
-       var i;
-       var slides = this.grid.children;
-       for (i=0 ; i<doc.children.length ; i++) {
-               this.grid.replaceChild(getCopyOfNode(doc.children[i]), slides[i]);
+       var i, node;
+       for (i=0 ; i<doc.childNodes.length ; i++) {
+               node = doc.childNodes[i];
+               if (node.nodeType === 1) {
+                       this.slides[i] = this.grid.replaceChild(getCopyOfNode(node), this.slides[i]);
+               }
        }
 };
 
        
        var url = absolute_url() +
                          '/portfolio_thumbnails_tail?start:int=' +
-                         String(this.grid.children.length + 1 ) +
+                         String(this.slides.length + 1 ) +
                          '&size:int=10';
        req.open('GET', url, true);
        req.send();
 
 Lightbox.prototype._appendTail = function(req) {
        var doc = req.responseXML.documentElement;
-       var i;
-       var slides = this.grid.children;
-       for (i=0 ; i<doc.children.length ; i++) {
-               this.lastSlide = this.grid.appendChild(getCopyOfNode(doc.children[i]));
+       var i, node;
+       for (i=0 ; i<doc.childNodes.length ; i++) {
+               node = doc.childNodes[i];
+               if (node.nodeType === 1) {
+                       this.lastSlide = this.grid.appendChild(getCopyOfNode(node));
+                       this.slides.push(this.lastSlide);
+               }
        }
        this.fetchingDisabled = false;
        if (doc.getAttribute('nomore')) {