Detecting check / uncheck in J2ME list

[paul.p.carey]

Hi

I'm creating a lcdui.List of type MULTIPLE and I'd like to display a
single checkbox 'All' that automatically checks or unchecks all the
other List elements. I haven't seen anything in the API to suggest how
do to this. Surely there's some callback that's invoked when an
element's state is changed - I'm guessing I just haven't found it, but
I'd be very grateful if someone could point it out to me.

I could always create a thread that polls the state of the elements,
but that would be rubbish...

Many thanks

Paul