a SystemWindow subclass and PluggableListMorph

I have attached the fileout of a subclass of SystemWindow I wrote.  It used
to work in 3.8.  Looking at the PluggableListMorph for #launcherList...built
in #buildWindow...

launchers instance variable has contents.

#notifyNewLauncher:nickname: is getting called when a new launcher is added.

It calls 'self changed: #launcherList', which updates dependents.  There are
no dependents.  Shouldn't there be with a PluggableListMorph?

Thanks for any help you can provide.
Rob