Hi, take a look at the code:

Qt Code: 
  1. class vnosTab : public QTabWidget {
  2. public:
  3. 	vnosTab();
  4.  
  5. private:
  6. 	QVBoxLayout *m_pTopLayoutVnos;
  7.  
  8. 	QPushButton *m_pVnosUvoznihCarinskih;
  9. 	QPushButton *m_pVnosUvoznihNecarinskih;
  10. 	QPushButton *m_pVnosIzvoznihCarinskih;
  11. 	QPushButton *m_pVnosIzvoznihNecarinskih;
  12. };
To copy to clipboard, switch view to plain text mode 

Qt Code: 
  1. vnosTab::vnosTab() {
  2. 	m_pTopLayoutVnos = new QVBoxLayout;	
  3. 	Q_CHECK_PTR(m_pTopLayoutVnos);
  4.  
  5. 	//buttons in tab "Vnos"
  6. 	m_pVnosUvoznihCarinskih = new QPushButton(trUtf8("uvoznih carinskih pošiljk"));
  7. 	Q_CHECK_PTR(m_pVnosUvoznihCarinskih);
  8. 	m_pVnosUvoznihNecarinskih = new QPushButton(trUtf8("uvoznih necarinskih pošiljk"));
  9. 	Q_CHECK_PTR(m_pVnosUvoznihNecarinskih);
  10. 	m_pVnosIzvoznihCarinskih = new QPushButton(trUtf8("izvoznih carinskih pošiljk"));
  11. 	Q_CHECK_PTR(m_pVnosIzvoznihCarinskih);
  12. 	m_pVnosIzvoznihNecarinskih = new QPushButton(trUtf8("izvoznih necarinskih pošiljk"));	
  13. 	Q_CHECK_PTR(m_pVnosIzvoznihNecarinskih);
  14.  
  15. 	m_pTopLayoutVnos->addWidget(m_pVnosUvoznihCarinskih);
  16. 	m_pTopLayoutVnos->addWidget(m_pVnosUvoznihNecarinskih);
  17. 	m_pTopLayoutVnos->addWidget(m_pVnosIzvoznihCarinskih);
  18. 	m_pTopLayoutVnos->addWidget(m_pVnosIzvoznihNecarinskih);
  19.  
  20. 	this->setLayout(m_pTopLayoutVnos);
  21. }
To copy to clipboard, switch view to plain text mode 


here I'm using the previously declared class
Qt Code: 
  1. void qKobilica::addToolMenu() {
  2. 	setWindowTitle("Kobilica:");
  3. 	m_pTopLayout = new QVBoxLayout();
  4. 	m_pToolbox = new QToolBox;
  5.  
  6. 	m_pTabSifrant = new QTabWidget;
  7. 	m_pTabVnos = new vnosTab();
  8. 	//m_pTabVnos->setHorizontalPolicy(QSizePolicy::Maximum);
  9. 	m_pTabNatisni = new QTabWidget;
  10.  
  11. 	//tabs
  12. 	m_pToolbox->addItem(m_pTabSifrant,trUtf8("Šifranti"));
  13. 	m_pToolbox->addItem(m_pTabVnos,trUtf8("Vnos"));
  14. 	m_pToolbox->addItem(m_pTabNatisni,trUtf8("Tiskanje"));
  15. 	m_pTopLayout->addWidget(m_pToolbox);
  16. 	//add the central menu to the application
  17. 	setCentralWidget(m_pToolbox);
  18.  
  19. }
To copy to clipboard, switch view to plain text mode 
What I want to do is to resize the buttons (there are 4 at the moment) that would fill the whole canvas (now there's some space in between those buttons), I want only buttons to be on the screen.