Gtk::Frame - how to respond to mouse-click event?

Hi. Consider this code here:

require ‘gtk2’

frame = Gtk::Frame.new(‘test’)
window = Gtk::Window.new
window.add frame
window.show_all
window.resize(500,500)
Gtk.main

Now I need to be able to respond to on-mouse-click events
on Gtk::Frame, but I don’t seem to get any signals when
I do so.

Help is greatly appreciated, perhaps I am missing something
obvious - most other widgets seem to respond nicely to
events.