Undo only works in main window of application

FROM : Wayne Pascoe
DATE : Sun Jun 25 22:07:15 2006

All,

I have a problem with an application. I am using Core Data for my 
data store, and the interface uses bindings to NSArrayController to 
present, add and modify the information.

In the main Window (window Outlet of AppDelegate) undo works fine. 
Any additions, removals or changes to values can be undone by 
pressing Apple-Z.

In all of the panels (I've only got the one window, everything else 
is a panel), undo does not work at all.

I've not implemented any undo features, just using what I got for 
free from Core Data. Do I have to implement any for these subsequent 
windows / panels?
If so, how do I go about integrating this with the NSArrayController? 
Do I have to subclass this for each NSArrayController I use?

Also, I'm not sure if this is related or not, but my window, all of 
my panels and my MainMenu all have a little yellow exclamation mark 
in the lower left of the icon. When I mouse over the icon, I get the 
following message: "One of the children has a bad / missing 
connection". Google doesn't tell me much about this error so I'm not 
sure if it's related or not.

Thanks in advance,

--
Wayne Pascoe    (gpg --keyserver www.co.uk.pgp.net --recv-keys 79A7C870)
You cannot apply a technological solution to
a sociological problem. (Edwards' Law)