Issue in CDatePicker control

[DeltaElectronics]

 have troubles in compiling the following method:

#include <Controls\DatePicker.mqh>

CDatePicker CFormDialog::createDate(x1,y1) {

   CDatePicker date;

   int x1 =10;

   int x2 =30;

   int y1 =20;

   int y2 =40;

//--- create

   if(!date.Create(m_chart_id,m_name+"Date",m_subwin,x1,y1,x2,y2))

      return(NULL);

   if(!Add(date))

      return(NULL);

   date.Value(TimeCurrent());

   

   return date;

}

But I got the following error on the last line 

return date

object of 'CDatePicker' cannot be returned, copy constructor 'CDatePicker::CDatePicker(const CDatePicker &)' not found test.mq5 42 11

What does exactly  mean ?

Is there a way to fix it ?