Refreshing of NSTableView with Snow Leopard

I'm having some trouble with refreshing my table views in Snow Leopard. I have a core data app with a NSTableView bound to a NSArrayController. In some situations the NSArrayController will get sorted externally and I need the table to refresh to show the new order.

Up until now I've always used:

	[myTableView reloadData];

...and this has worked. However, on Snow Leopard it doesn't - nothing changes. Exactly the same code on Leopard and earlier works exactly as I would expect. I have even tried [myTableView setNeedsDisplay: YES] although I assume that under the hood the reloadData method is doing this anyway.

There's nothing in the documentation to say that reloadData is depreciated... any help would be GREATLY appreciated!

Thanks,
Trent.