🚀 go-pugleaf

I am using interviews 	and  have some problem making a part of my
code work.

As a matter of fact I am having problems with updating a object called
  View which is derived from GraphicBlock. I capture an event 
and try to append a graphic(rectangle)  to the picture( which was 
passed to the constructor of View) and then call Update on the view. 
It gives me an error at Update.  

I even tried a simple program to insert  a rectangle into a View( inherited 
from GraphicBlock)   

class Minidraw;

class View:public GraphicBlock{
public:
        View(Rect*);
};
class Minidraw:public MonoScene{
public:
        Minidraw();
        Interactor * Interior(View *);
};
Minidraw::Minidraw()
{
        Rect * rect = new Rect(0,0,10,10);
        rect->SetColors(pblack, pwhite);
        rect->SetBrush(psingle);
        rect->SetPattern(psolid);
        rect->FillBg(true);
	View * view = new View(rect);
        Insert(new Frame(Interior(view)));
}

View::View(Rect * r):(nil, r)
{
	input = new Sensor(updownEvents);
        shape->width = round(20*cm);
        shape->height = round(10*cm);
}

Interactor * Minidraw::Interior(View *v)
{
        return new HBox(v);
}

main( int argc, char **argv){
        World* world = new World("minidraw", argc, argv);
        world->Insert(new Minidraw);
        world->Run();
}

this program gave me a CORE dump when the constructor for
the View was called.

Any kind of help will appreciated  very much.