Sorry to file a bug about this.  I'm trying to wrap GSimpleAction for the C++ bindings and ran into a little bit of a problem.  The problem is that since it doesn't define its GSimpleActionClass the way it is usually done with other GObject derived classes, it makes it difficult to wrap its signals.  This happens because there is no way for a derived class to write a class init function that sets the signal members of the GSimpleActionClass to custom callbacks so that the custom callbacks can receive the signals and forward them to the C++ handlers.  Can GSimpleAction's code be modified somehow so that wrapping its signals is possible for the C++ bindings?