Hi

I'va a simple window (QMainWindow):

Qt Code: 
  1. FormTransportOperacje::FormTransportOperacje(QString ID_transport, QWidget *parent) : QMainWindow(parent)
  2. {
  3.     this->setMaximumHeight(400);
  4.     QWidget *base = new QWidget();
  5.     QGridLayout *layout = new QGridLayout(base);
  6.     QSqlQuery query("SELECT Imie, Nazwisko, Data_operacji, Nazwa_operacji FROM m_transporty_operacje AS Top LEFT JOIN m_uzytkownicy AS U ON (U.ID_u=Top.ID_uzytkownik) WHERE ID_transport="+ID_transport+" ORDER BY Data_operacji DESC");
  7.  
  8.     int i = 0;
  9.     while (query.next()) {       
  10.         QGroupBox *GbTMP= new QGroupBox(query.value(3).toString());        
  11.         GbTMP->setMinimumHeight(70);
  12.         GbTMP->setMaximumHeight(70);
  13.         QGridLayout *layoutTMP = new QGridLayout();
  14.         QDateTime DTData = query.value(2).toDateTime();
  15.  
  16.         QLabel *Uzytkownik = new QLabel(query.value(0).toString()+" "+query.value(1).toString());
  17.         QLabel *Data_operacji = new QLabel(DTData.toString("yyyy-MM-dd HH:mm:ss"));
  18.  
  19.         GbTMP->setLayout(layoutTMP);
  20.         layout->addWidget(GbTMP,i++,0,1,1);
  21.     }
  22.  
  23.     base->show();
  24.     this->setCentralWidget(base);
  25.     this->move(((QApplication::desktop()->width()-this->width())/2),((QApplication::desktop()->height()-this->height())/2));
  26.  
  27. }
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And when there are many records, the window extends beyond the boundary of screen.

How can I "freez" the size of window, and add the verticalslider when the content does not fit in the window?