[gtkmm] signal handlers vs. virtual functions

[Davide Rossetti <rossetti apemaia roma1 infn it>]

hi gtk-- users, 
I have a mothodological question:  
when is "good" to override X_impl() virtual functions in gtk-- widgets ?  

as I understand it:

1) for main windows C++ classes (as dialog, toplevel)  use
   connect_to_method() to grab signals from plain gtk-- widgets that they
   `contain' as member objects

2) for personalised widget classes, subclassed from stock gtk-- widget
   classes, there are two options available:
	2.1) use connect_to_method(X, this, handle_X_method);
	2.2) override X_impl().

(2.2) can give problems: either it is a do nothing function [is it
true?] or there is 'meat' inside and you have to call the
Super::X_impl() right inside your X_impl() [and you have to
remember/know when to call it before or after your processing]

What are your suggestions ?

I went into this thought writing a simple gtk-- program taking
hello.cc as a guide.

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