title: PyQt: Adding widgets to scrollarea during the runtime
body: <p>I'm trying to add new widgets (in the example below I use labels) during the runtime by pressing on a button. Here the example:</p>
  
  <pre><code>import sys
  from PyQt4.QtCore import *
  from PyQt4.QtGui import *
  
  class Widget(QWidget):
  
      def __init__(self, parent= None):
          super(Widget, self).__init__()
  
          btn_new = QPushButton("Append new label")
          self.connect(btn_new, SIGNAL('clicked()'), self.add_new_label)
  
          #Container Widget       
          self.widget = QWidget()
          #Layout of Container Widget
          layout = QVBoxLayout(self)
          for _ in range(20):
              label = QLabel("test")
              layout.addWidget(label)
          self.widget.setLayout(layout)
  
          #Scroll Area Properties
          scroll = QScrollArea()
          scroll.setVerticalScrollBarPolicy(Qt.ScrollBarAlwaysOn)
          scroll.setHorizontalScrollBarPolicy(Qt.ScrollBarAlwaysOff)
          scroll.setWidgetResizable(False)
          scroll.setWidget(self.widget)
  
          #Scroll Area Layer add
          vLayout = QVBoxLayout(self)
          vLayout.addWidget(btn_new)
          vLayout.addWidget(scroll)
          self.setLayout(vLayout)
  
      def add_new_label(self):
          label = QLabel("new")
          self.widget.layout().addWidget(label)
  
  
  if __name__ == '__main__':
      app = QApplication(sys.argv)
  
      dialog = Widget()
      dialog.show()
  
      app.exec_()
  </code></pre>
  
  <p>When I start the application everything looks ok, the list of labels is correctly shown and their size is also correct. But, when I press several times on the button to add new labels, the new ones are added to the list but their size change. All labels of the list go smaller.</p>
  
  <p>How do I fix this error?</p>