Collection of widgets need to generate 'leave' signal

[Kent Schumacher <kent structural-wood com>]

I've built a widget (item_widget) that is a collection of entry and button widgets.

I would like to generate 'enter' and 'leave' signals when focus enters or leaves
the item_widget.

I've been able to generate the 'enter' signal by having a flag in the item_widget
that indicates whether the item_widget has been entered.  If one of the sub-widgets
receives focus, I check the item_widget entered flag and if it is not set I generate an
'enter' signal and then set the entered flag.

Unfortunately I haven't figured out how to determine when every sub widget in item_widget
has lost focus, so I'm unable to generate a 'leave' signal.

Has anyone dealt with this situation before?  Does anyone have any suggestions on
how to implement this behavior?