gtkmm2.22 ComboBox on_button_press_event

[Damon Register <damon w register lmco com>]

Hello list and thanks to all who have spent so much of their time
on this gtkmm project.  I am trying to find info on getting the
on_button_press_event from a ComboBox.  I have kept the e-mail from
this list since 2002.  I see there are some like Murray Cumming
who have been contributing for at least 17 years.  Thanks!

Here is the problem.  I have learned how to use the ComboBox with
a lot of help from this tutorial:
https://developer.gnome.org/gtkmm-tutorial/2.22/sec-combobox.html.en

The ComboBox works fine but I would like to be able to intercept
the mouse clicks as I do for other widgets using on_button_press_event()
but so far I have not been able to accomplish this.  I have tried
using a standard ComboBox like this

Gtk::ComboBox m_Combo;

m_combo->signal_button_press_event().connect(sigc::mem_fun(*this,
  &hello::on_button_press_event) );

but my on_button_press_event() is never called.

I have tried deriving my own ComboBox from the Gtk::ComboBox and
attempting to get the on_button_press_event() in MyComboBox but
that didn't work either.  Can anyone please show me how to
intercept the button clicks?

Although I don't totally understand, I see from the last 17 years
of e-mail, The combo has had its issues and seems to have made
some significant chances between gtkmm 2.22 and 2.24.  I am wondering
if what I am seeing is just a bug that has already been fixed.
Is this the case?

I suppose that the questions have to be asked: why am I still using
2.22 instead of 2.24 or later, or why haven't I moved on to gtkmm 3.x?
I have stuck with 2.22 because that is the last known (to me) version
of gtkmm all-in-one installers for gtkmm2 which I got here:
http://ftp.gnome.org/pub/gnome/binaries/win32/gtkmm/2.22/

I have not found any easy method for 2.4 in Windows.  I have tried a
few times to move on to gtkmm3 but gut stuck on fixing ugly oversized
widgets and have not been able to get anywhere with themes.  So it
comes down to these questions:
1. can I get the button clicks in 2.22?
2. is it time to throw in the towel and move to gtkmm3?
3. if yes to Q2, can anyone help me with the theme problem?

I have been trying to find info on themes in the Windows/gtkmm
world but haven't yet found enough to understand.  I did find
mention of settings.ini but no clear picture of where it should
be or where themes reside (other than under each application).

Damon Register