Question about emitted signals

[Adrián Ortega <elfus0 1 gmail com>]

I've been looking at the Gtkmm reference and the signals on each class and I find it useful but I still have a huge question about the signals. I know the name for signals prototype in the reference are made to show when the signal is emitted, e.g.   the class Gtk::Button has the signals

Glib::SignalProxy0<void>	signal_activate ()
Glib::SignalProxy0<void>	signal_clicked ()
Glib::SignalProxy0<void>	signal_enter ()
Glib::SignalProxy0<void>	signal_leave ()
Glib::SignalProxy0<void>	signal_pressed ()

I know the signal "signal_clicked" is emitted when the button is clicked, and the signal "signal_pressed()" is emitted when the button is pressed, but I don't know when the signal "signal_activate()" is emitted. 
Another example would be in the class Gtk::MenuItem, I don't know the difference about the signals "signal_activate()" and "signal_activate_item()".

So the main question is, is there some kind of reference where I can check when  each signal is emitted? sorry if this question may sound too dumb but sometimes I have a hard time trying to figure out when a certain signal is emitted as English is not my native language (that may be why I have this little problem).

Thanks in advance.
Adrián Ortega