CAppDialog create problem when the timeframe change ( from an Example of Metaquotes)

Hi! 

The following code is an example of metaquotes. 

#include <Controls\Dialog.mqh> 
#include <Controls\CheckBox.mqh> 
//+------------------------------------------------------------------+ 
//| defines                                                          | 
//+------------------------------------------------------------------+ 
//--- indents and gaps 
#define INDENT_LEFT                         (11)      // indent from left (with allowance for border width) 
#define INDENT_TOP                          (11)      // indent from top (with allowance for border width) 
#define INDENT_RIGHT                        (11)      // indent from right (with allowance for border width) 
#define INDENT_BOTTOM                       (11)      // indent from bottom (with allowance for border width) 
#define CONTROLS_GAP_X                      (5)       // gap by X coordinate 
#define CONTROLS_GAP_Y                      (5)       // gap by Y coordinate 
//--- for buttons 
#define BUTTON_WIDTH                        (100)     // size by X coordinate 
#define BUTTON_HEIGHT                       (20)      // size by Y coordinate 
//--- for the indication area 
#define EDIT_HEIGHT                         (20)      // size by Y coordinate 
//--- for group controls 
#define GROUP_WIDTH                         (150)     // size by X coordinate 
#define LIST_HEIGHT                         (179)     // size by Y coordinate 
#define RADIO_HEIGHT                        (56)      // size by Y coordinate 
#define CHECK_HEIGHT                        (93)      // size by Y coordinate 
//+------------------------------------------------------------------+ 
//| Class CControlsDialog                                            | 
//| Usage: main dialog of the Controls application                   | 
//+------------------------------------------------------------------+ 
class CControlsDialog : public CAppDialog 
  { 
private: 
   CCheckBox         m_check_box1;                    // CCheckBox object 
   CCheckBox         m_check_box2;                    // CCheckBox object 
public: 
                     CControlsDialog(void); 
                    ~CControlsDialog(void); 
   //--- create 
   virtual bool      Create(const long chart,const string name,const int subwin,const int x1,const int y1,const int x2,const int y2); 
   //--- chart event handler 
   virtual bool      OnEvent(const int id,const long &lparam,const double &dparam,const string &sparam); 
protected: 
   //--- create dependent controls 
   bool              CreateCheckBox1(void); 
   bool              CreateCheckBox2(void); 
   //--- handlers of the dependent controls events 
   void              OnChangeCheckBox1(void); 
   void              OnChangeCheckBox2(void); 
  }; 
//+------------------------------------------------------------------+ 
//| Event Handling                                                   | 
//+------------------------------------------------------------------+ 
EVENT_MAP_BEGIN(CControlsDialog) 
ON_EVENT(ON_CHANGE,m_check_box1,OnChangeCheckBox1) 
ON_EVENT(ON_CHANGE,m_check_box2,OnChangeCheckBox2) 
EVENT_MAP_END(CAppDialog) 
//+------------------------------------------------------------------+ 
//| Constructor                                                      | 
//+------------------------------------------------------------------+ 
CControlsDialog::CControlsDialog(void) 
  { 
  } 
//+------------------------------------------------------------------+ 
//| Destructor                                                       | 
//+------------------------------------------------------------------+ 
CControlsDialog::~CControlsDialog(void) 
  { 
  } 
//+------------------------------------------------------------------+ 
//| Create                                                           | 
//+------------------------------------------------------------------+ 
bool CControlsDialog::Create(const long chart,const string name,const int subwin,const int x1,const int y1,const int x2,const int y2) 
  { 
   if(!CAppDialog::Create(chart,name,subwin,x1,y1,x2,y2)) 
      return(false); 
//--- create dependent controls 
   if(!CreateCheckBox1()) 
      return(false); 
   if(!CreateCheckBox2()) 
      return(false); 
//--- succeed 
   return(true); 
  } 
//+------------------------------------------------------------------+ 
//| Create the "CheckBox" element                                    | 
//+------------------------------------------------------------------+ 
bool CControlsDialog::CreateCheckBox1(void) 
  { 
//--- coordinates 
   int x1=INDENT_LEFT; 
   int y1=INDENT_TOP+(EDIT_HEIGHT+CONTROLS_GAP_Y)+ 
          (BUTTON_HEIGHT+CONTROLS_GAP_Y)+ 
          (EDIT_HEIGHT+CONTROLS_GAP_Y)+ 
          (EDIT_HEIGHT+CONTROLS_GAP_Y)+ 
          (RADIO_HEIGHT+CONTROLS_GAP_Y); 
   int x2=x1+GROUP_WIDTH; 
   int y2=y1+BUTTON_HEIGHT; 
//--- create 
   if(!m_check_box1.Create(m_chart_id,m_name+"CheckBox1",m_subwin,x1,y1,x2,y2)) 
      return(false); 
   if(!m_check_box1.Text("CheckBox1")) 
      return(false); 
   if(!m_check_box1.Color(clrBlue)) 
      return(false); 
   if(!Add(m_check_box1)) 
      return(false); 
//--- succeed 
   return(true); 
  } 
//+------------------------------------------------------------------+ 
//| Create the "CheckBox" element                                    | 
//+------------------------------------------------------------------+ 
bool CControlsDialog::CreateCheckBox2(void) 
  { 
//--- coordinates 
   int x1=INDENT_LEFT+GROUP_WIDTH+CONTROLS_GAP_X; 
   int y1=INDENT_TOP+(EDIT_HEIGHT+CONTROLS_GAP_Y)+ 
          (BUTTON_HEIGHT+CONTROLS_GAP_Y)+ 
          (EDIT_HEIGHT+CONTROLS_GAP_Y)+ 
          (EDIT_HEIGHT+CONTROLS_GAP_Y)+ 
          (RADIO_HEIGHT+CONTROLS_GAP_Y); 
   int x2=x1+GROUP_WIDTH; 
   int y2=y1+BUTTON_HEIGHT; 
//--- create 
   if(!m_check_box2.Create(m_chart_id,m_name+"CheckBox2",m_subwin,x1,y1,x2,y2)) 
      return(false); 
   if(!m_check_box2.Text("CheckBox2")) 
      return(false); 
   if(!m_check_box2.Color(clrBlue)) 
      return(false); 
   if(!Add(m_check_box2)) 
      return(false); 
   m_check_box2.Checked(true); 
   Comment(__FUNCTION__+" : Checked="+IntegerToString(m_check_box2.Checked())); 
//--- succeed 
   return(true); 
  } 
//+------------------------------------------------------------------+ 
//| Event handler                                                    | 
//+------------------------------------------------------------------+ 
void CControlsDialog::OnChangeCheckBox1(void) 
  { 
   Comment(__FUNCTION__+" : Checked="+IntegerToString(m_check_box1.Checked())); 
  } 
//+------------------------------------------------------------------+ 
//| Event handler                                                    | 
//+------------------------------------------------------------------+ 
void CControlsDialog::OnChangeCheckBox2(void) 
  { 
   Comment(__FUNCTION__+" : Checked="+IntegerToString(m_check_box2.Checked())); 
  } 
//+------------------------------------------------------------------+ 
//| Global Variables                                                 | 
//+------------------------------------------------------------------+ 
CControlsDialog ExtDialog; 
//+------------------------------------------------------------------+ 
//| Expert initialization function                                   | 
//+------------------------------------------------------------------+ 
int OnInit() 
  { 
//--- create application dialog 
   if(!ExtDialog.Create(0,"Controls",0,40,40,380,344)) 
      return(INIT_FAILED); 
//--- run application 
   ExtDialog.Run(); 
//--- succeed 
   return(INIT_SUCCEEDED); 
  } 
//+------------------------------------------------------------------+ 
//| Expert deinitialization function                                 | 
//+------------------------------------------------------------------+ 
void OnDeinit(const int reason) 
  { 
//--- 
   Comment(""); 
//--- destroy dialog 
   ExtDialog.Destroy(reason); 
  } 
//+------------------------------------------------------------------+ 
//| Expert chart event function                                      | 
//+------------------------------------------------------------------+ 
void OnChartEvent(const int id,         // event ID   
                  const long& lparam,   // event parameter of the long type 
                  const double& dparam, // event parameter of the double type 
                  const string& sparam) // event parameter of the string type 
  { 
   ExtDialog.ChartEvent(id,lparam,dparam,sparam); 
  }

If this code implemented to MQL5 and change the timeframe it is working fine like the picture below :

but if this code implemented to MQL4 and change the timeframe it doesn't work properly :

It seem to create extra objects every time i change the timeframe 

Any idea to solve that problem ?

Thanks!