Accessing widgets using their parents/containers

[Lance Duivenbode <huku iinet net au>]

Hi,

I was just wondering if it was possible to access widgets when you only 
have their parents. For example, if I add a checkbox to a window that 
can only be enabled when I check another checkbox, can I then activate 
the first checkbox from within the second checkbox's callback function - 
without making both of them static and/or global?

Thanks,
Lance