==4445== Invalid read of size 4
==4445==    at 0x69EB1B6: XInternAtom (in /usr/lib/libX11.so.6.3.0)
==4445==    by 0x8191FDB: Upp::XAtomRaw(char const*) (X11App.cpp:15)
==4445==    by 0x81920EA: Upp::XAtom(char const*) (X11App.cpp:26)
==4445==    by 0x8187B92: Upp::Ctrl::IsCompositedGui() (X11Wnd.cpp:662)
==4445==    by 0x8167695: Upp::Ctrl::Ctrl() (Ctrl.cpp:560)
==4445==    by 0x80A3DD4: Upp::ParentCtrl::ParentCtrl() (Static.cpp:202)
==4445==    by 0x80532DE: ScatterDemo::ScatterDemo() (ScatterCtrl_Demo.h:16)
==4445==    by 0x80607C4: WithTab10<ScatterDemo>::WithTab10() (ScatterCtrl_Demo.lay:62)
==4445==    by 0x806089C: Tab10::Tab10() (ScatterCtrl_Demo.h:153)
==4445==    by 0x806001F: s__s69_fn() (tab10.cpp:70)
==4445==    by 0x805223C: Upp::Callinit::Callinit(void (*)(), char const*, int) (Defs.h:169)
==4445==    by 0x806014D: __static_initialization_and_destruction_0(int, int) (tab10.cpp:69)
==4445==  Address 0x4d0 is not stack'd, malloc'd or (recently) free'd

SetMajorUnitsNum(10,10);

class DataSource {
public:
	typedef double (DataSource::*Getdatafun)(int id);

	DataSource() : isParam(false) {}
	virtual ~DataSource() {};	
	virtual double z(int id) 	{return Null;};
	virtual double y(int id) 	{return Null;};
	virtual double x(int id) 	{return Null;};
	virtual int GetCount()		{return Null;};
	bool IsParam()				{return isParam;};

	virtual double MinX() {return Min(&DataSource::x);}	
	virtual double MinY() {return Min(&DataSource::y);}	
	virtual double MinZ() {return Min(&DataSource::z);}	

	virtual double MaxX() {return Max(&DataSource::x);}				
	virtual double MaxY() {return Max(&DataSource::y);}	
	virtual double MaxZ() {return Max(&DataSource::z);}	

	virtual double AvgX() {return Avg(&DataSource::x);}	
	virtual double AvgY() {return Avg(&DataSource::y);}					
	virtual double AvgZ() {return Avg(&DataSource::z);}	

template<class DATASOURCE = DataSource>
class ScatterDraw {
public:
...

template<int NBPOINTS>
class DataSource {
private:
	double _x[NBPOINTS];
	double _y[NBPOINTS];
	double _z[NBPOINTS];
public:

DataSource() {}
inline double z(int id) 	{return _x[id];}
inline double y(int id) 	{return _y[id];}
inline double x(int id) 	{return _z[id];}
inline int GetCount()		{return NBPOINTS;}
inline bool IsParam()		{return false;}

inline double MinX() {return ....;}	
inline double MinY() {return ....;}	
inline double MinZ() {return ....;}	

inline double MaxX() {return ....;}				
inline double MaxY() {return ....;}	
inline double MaxZ() {return ....;}	

inline double AvgX() {return ....;}	
inline double AvgY() {return ....;}					
inline double AvgZ() {return ....;}	
};

	static Color GetNewColor(int id);
	static String GetNewDash(int id);
	static MarkPlot *GetNewMarkPlot(int id);

virtual void SetScale(int  scale) {}

Color GetNewColor(int id);
String GetNewDash(int id);
MarkPlot *GetNewMarkPlot(int id);

Scatter::Refresh()

Color GetNewColor(int id);
String GetNewDash(int id);
MarkPlot *GetNewMarkPlot(int id);

class a : public B {};

class OriginalClass {
	public:
	OriginalClass() {}
	OriginalClass& fctA() { .....; return *this; }
	OriginalClass& fctD() { .....; return *this; }
};

OriginalClass inst;
isnt.fctA().fctB();

class BaseClass {
	public:
	BaseClass() {}
	BaseClass& fctA() { .....; return *this; }
};
class DerivedClass : public  BaseClass {
	public:
	DerivedClass() {}
	DerivedClass& fctD() { return *this; }
};

DerivedClass inst;
isnt.fctA().fctB();    ==> compilation error

template<class DERIVED>
class BaseClass {
	public:
	BaseClass() {}
	DERIVED& fctA() { return *static_cast<DERIVED*>(this); }
};
class DerivedClass : public  BaseClass<DerivedClass> {
	public:
	DerivedClass() {}
	DerivedClass& fctD() { return *this; }
};

DerivedClass inst;
isnt.fctA().fctB();

Yes I know, but without this, I can't take advantage of you're code, and interface will probably diverge