Front Stack/Window???

[David Burgun]

Hi,

Is there a message that gets sent to a stack when it becomes the 
front most window? e.g. when it is selected by the user, e.g. if 
there are two stacks:

StackA and StackB,

  if StackB is selected and the user then clicks into StackA )
  I would like Stack A to know this fact?

For StackB to know that is has been de-selected would be good too!

Depending on which stack/window is selected I would like to be able 
to perform a different action in another "Common" (library) stack. Is 
this possible?

Thanks a lot
Dave