Invalid argument JavaScript exception in IE 8 issue with ExtJS in moveItem function

Question

Below is a code snippet from the file ext-all-dev.js. The JavaScript exception below only happens in Internet Explorer 8 (IE). I have not tried any other versions of Internet Explorer. When I place a break-point on this line of code when running my application, the browser freezes in IE. So I don't have a way to troubleshoot this in IE. Is there an easy way to tell what code might be calling this line? I'm getting a sense that some drag and drop functionality may be causing this (because of the function comment), but that's a guess. My only option right now is to start tracing backwards using Google Chrome or Mozilla Firefox. I'm just looking for advice on troubleshooting unless you know what might cause this.

/**
 * Moves Component to the provided target instead.
 * @private
 */
moveItem : function(item, target, position) {
        target = target.dom || target;
        if (typeof position == 'number') {
            position = target.childNodes[position];
        }
        target.insertBefore(item.el.dom, position || null);  // line 51942
        item.container = Ext.get(target);
        this.configureItem(item);
    },

Exception:

Invalid argument.
ext-all-dev.js line 51942 character 9

Answer 1

Placed the tree drag and drop plugin fully qualified class name into the requires config.