...but is good in IE8.

In IE7, even though I've set the first node to 'expanded', the children are not shown. The twistie indiciates that we've children, but these rows are not shown.

IE7 screenshot.jpg

The children reappear if you close the twistie, and then reopen.

In IE8, you can see the expected behaviour.

IE8 screenshot.jpg

This appears to only be a problem for data in which there's only one top-level node.

Has anyone seen this type of behaviour before?