class MyFile
{
    MyFile (TabCtrl &tabs) { tab = tabs.Add("..."); }

    GLCtrl         gl;
    TabCtrl::Item &tab;
};
//...
class MainWindow
{
    TabCtrl        tabs;
    Vector<MyFile> files;
};
//...
void MainWindow::OnNew()
{
    
    files.Add(MyFile(tabs));
}

class MyFile : public GLCtrl {
    MyFile();

    virtual void GLPaint();
    //...
};
//...
class MainWindow : public TopWindow
{
    TabCtrl        tabs;
    Array<MyFile> files;
};
//...
void MainWindow::OnNew()
{
    
    MyFile &file = files.Create<MyFile>();
    file.SizePos();
    tabs.Add(file, "filename");
}

GLCtrl gl;
gl.WhenGLPaint = THISBACK(MyGLPaint);

struct BaseClass
{
	BaseClass() { int1 = 1; }	
	
	int int1;
	virtual int 	GetInt() 		{ return int1; }
	virtual String 	GetString() 	{ return "A String"; }
};

struct DerivedClass : public BaseClass, public Moveable<DerivedClass>
{
	DerivedClass() { int2 = 99; }	
	
	int int2;
	virtual int 	GetInt() 		{ return int2; }
	virtual String 	GetString() 	{ return "This is a derived class"; }
};

GUI_APP_MAIN
{
	Vector<DerivedClass> v;
	
	v.Add(DerivedClass());
	v.Add(DerivedClass());
	
	for (int i = 0; i < v.GetCount(); i++)
		PromptOK(Format("Int: %d String: %s", v[i].GetInt(), v[i].GetString()));
}