I've got a simple tree - nothing groundbreaking, works perfectly fine in Firefox and fails miserably in IE8. No JavaScript errors are shown - the tree simply doesn't render any nodes.

Here's the tree code:

Code:
MyPanel7Ui = Ext.extend(Ext.tree.TreePanel, {
    title: 'Data',
    rootVisible: false,
    autoScroll: true,
    autoShow: true,
    id: 'DataTree',
    initComponent: function() {
        this.root = {
            text: 'Tree Node',
            singleClickExpand: true
        };
        this.loader = {
            url: '/sd/ajax/tree.aspx',
            requestMethod: 'GET',
            preloadChildren: true
        };
        MyPanel7Ui.superclass.initComponent.call(this);
    }
});
The ajax call to load the tree data is made and comes back - I've traced it with Fiddler. Here's the actual response:

Code:
HTTP/1.1 200 OK
Server: Microsoft-IIS/5.1
Date: Tue, 05 Oct 2010 19:14:25 GMT
X-Powered-By: ASP.NET
X-AspNet-Version: 2.0.50727
Cache-Control: private
Content-Type: text/plain; charset=utf-8
Content-Length: 7169

[
{
id: 2010,
text: '2010 Data',
iconCls: 'tabEpisodeList',
cls: 'nodeYear',
singleClickExpand: true,
expanded: true,
children: [
{
id: '10/2010',
text: 'October',
iconCls: 'uncertified',
cls: 'nodeMonth',
leaf: true,
href: '/2010/10',
},
{
id: '9/2010',
text: 'September',
iconCls: 'uncertified',
cls: 'nodeMonth',
leaf: true,
href: '/2010/09',
},
{
id: '8/2010',
text: 'August',
iconCls: 'uncertified',
cls: 'nodeMonth',
leaf: true,
href: '/2010/08',
},
{
id: '7/2010',
text: 'July',
iconCls: 'uncertified',
cls: 'nodeMonth',
leaf: true,
href: '/2010/07',
},
{
id: '6/2010',
text: 'June',
iconCls: 'uncertified',
cls: 'nodeMonth',
leaf: true,
href: '/2010/06',
},
{
id: '5/2010',
text: 'May',
iconCls: 'uncertified',
cls: 'nodeMonth',
leaf: true,
href: '/2010/05',
},
{
id: '4/2010',
text: 'April',
iconCls: 'certified',
cls: 'nodeMonth',
leaf: true,
href: '/2010/04',
},
{
id: '3/2010',
text: 'March',
iconCls: 'certified',
cls: 'nodeMonth',
leaf: true,
href: '/2010/03',
},
{
id: '2/2010',
text: 'February',
iconCls: 'certified',
cls: 'nodeMonth',
leaf: true,
href: '/2010/02',
},
{
id: '1/2010',
text: 'January',
iconCls: 'certified',
cls: 'nodeMonth',
leaf: true,
href: '/2010/01',
}
]
},
{
id: 2009,
text: '2009 Data',
iconCls: 'tabEpisodeList',
cls: 'nodeYear',
singleClickExpand: true,
expanded: false,
children: [
{
id: '12/2009',
text: 'December',
iconCls: 'certified',
cls: 'nodeMonth',
leaf: true,
href: '/2009/12',
},
{
id: '11/2009',
text: 'November',
iconCls: 'certified',
cls: 'nodeMonth',
leaf: true,
href: '/2009/11',
},
{
id: '10/2009',
text: 'October',
iconCls: 'certified',
cls: 'nodeMonth',
leaf: true,
href: '/2009/10',
},
{
id: '9/2009',
text: 'September',
iconCls: 'certified',
cls: 'nodeMonth',
leaf: true,
href: '/2009/09',
},
{
id: '8/2009',
text: 'August',
iconCls: 'certified',
cls: 'nodeMonth',
leaf: true,
href: '/2009/08',
},
{
id: '7/2009',
text: 'July',
iconCls: 'certified',
cls: 'nodeMonth',
leaf: true,
href: '/2009/07',
},
{
id: '6/2009',
text: 'June',
iconCls: 'certified',
cls: 'nodeMonth',
leaf: true,
href: '/2009/06',
},
{
id: '5/2009',
text: 'May',
iconCls: 'certified',
cls: 'nodeMonth',
leaf: true,
href: '/2009/05',
},
{
id: '4/2009',
text: 'April',
iconCls: 'certified',
cls: 'nodeMonth',
leaf: true,
href: '/2009/04',
},
{
id: '3/2009',
text: 'March',
iconCls: 'certified',
cls: 'nodeMonth',
leaf: true,
href: '/2009/03',
},
{
id: '2/2009',
text: 'February',
iconCls: 'certified',
cls: 'nodeMonth',
leaf: true,
href: '/2009/02',
},
{
id: '1/2009',
text: 'January',
iconCls: 'certified',
cls: 'nodeMonth',
leaf: true,
href: '/2009/01',
}
]
},
{
id: 2008,
text: '2008 Data',
iconCls: 'tabEpisodeList',
cls: 'nodeYear',
singleClickExpand: true,
expanded: false,
children: [
{
id: '12/2008',
text: 'December',
iconCls: 'certified',
cls: 'nodeMonth',
leaf: true,
href: '/2008/12',
},
{
id: '11/2008',
text: 'November',
iconCls: 'certified',
cls: 'nodeMonth',
leaf: true,
href: '/2008/11',
},
{
id: '10/2008',
text: 'October',
iconCls: 'certified',
cls: 'nodeMonth',
leaf: true,
href: '/2008/10',
},
{
id: '9/2008',
text: 'September',
iconCls: 'certified',
cls: 'nodeMonth',
leaf: true,
href: '/2008/09',
},
{
id: '8/2008',
text: 'August',
iconCls: 'certified',
cls: 'nodeMonth',
leaf: true,
href: '/2008/08',
},
{
id: '7/2008',
text: 'July',
iconCls: 'certified',
cls: 'nodeMonth',
leaf: true,
href: '/2008/07',
},
{
id: '6/2008',
text: 'June',
iconCls: 'certified',
cls: 'nodeMonth',
leaf: true,
href: '/2008/06',
},
{
id: '5/2008',
text: 'May',
iconCls: 'certified',
cls: 'nodeMonth',
leaf: true,
href: '/2008/05',
},
{
id: '4/2008',
text: 'April',
iconCls: 'certified',
cls: 'nodeMonth',
leaf: true,
href: '/2008/04',
},
{
id: '3/2008',
text: 'March',
iconCls: 'certified',
cls: 'nodeMonth',
leaf: true,
href: '/2008/03',
},
{
id: '2/2008',
text: 'February',
iconCls: 'certified',
cls: 'nodeMonth',
leaf: true,
href: '/2008/02',
},
{
id: '1/2008',
text: 'January',
iconCls: 'certified',
cls: 'nodeMonth',
leaf: true,
href: '/2008/01',
}
]
},
{
id: 2007,
text: '2007 Data',
iconCls: 'tabEpisodeList',
cls: 'nodeYear',
singleClickExpand: true,
expanded: false,
children: [
{
id: '12/2007',
text: 'December',
iconCls: 'certified',
cls: 'nodeMonth',
leaf: true,
href: '/2007/12',
},
{
id: '11/2007',
text: 'November',
iconCls: 'certified',
cls: 'nodeMonth',
leaf: true,
href: '/2007/11',
},
{
id: '10/2007',
text: 'October',
iconCls: 'certified',
cls: 'nodeMonth',
leaf: true,
href: '/2007/10',
},
{
id: '9/2007',
text: 'September',
iconCls: 'certified',
cls: 'nodeMonth',
leaf: true,
href: '/2007/09',
},
{
id: '8/2007',
text: 'August',
iconCls: 'certified',
cls: 'nodeMonth',
leaf: true,
href: '/2007/08',
},
{
id: '7/2007',
text: 'July',
iconCls: 'certified',
cls: 'nodeMonth',
leaf: true,
href: '/2007/07',
},
{
id: '6/2007',
text: 'June',
iconCls: 'certified',
cls: 'nodeMonth',
leaf: true,
href: '/2007/06',
},
{
id: '5/2007',
text: 'May',
iconCls: 'certified',
cls: 'nodeMonth',
leaf: true,
href: '/2007/05',
},
{
id: '4/2007',
text: 'April',
iconCls: 'certified',
cls: 'nodeMonth',
leaf: true,
href: '/2007/04',
},
{
id: '3/2007',
text: 'March',
iconCls: 'certified',
cls: 'nodeMonth',
leaf: true,
href: '/2007/03',
},
{
id: '2/2007',
text: 'February',
iconCls: 'certified',
cls: 'nodeMonth',
leaf: true,
href: '/2007/02',
},
{
id: '1/2007',
text: 'January',
iconCls: 'certified',
cls: 'nodeMonth',
leaf: true,
href: '/2007/01',
}
]
},
{
id: 2006,
text: '2006 Data',
iconCls: 'tabEpisodeList',
cls: 'nodeYear',
singleClickExpand: true,
expanded: false,
children: [
{
id: '12/2006',
text: 'December',
iconCls: 'certified',
cls: 'nodeMonth',
leaf: true,
href: '/2006/12',
},
{
id: '11/2006',
text: 'November',
iconCls: 'certified',
cls: 'nodeMonth',
leaf: true,
href: '/2006/11',
},
{
id: '10/2006',
text: 'October',
iconCls: 'certified',
cls: 'nodeMonth',
leaf: true,
href: '/2006/10',
},
]
}
]
Anyone have ideas what's going on here? Am I missing a setting; is the MIME type wrong? Could this be an actual bug in the ExtJS code?