title: Set size for QGroupbox?
body: <p>I'm new guy, and i start with new simple GUI application, I follow some tutorial on the internet and now i have a trouble with QGroupbox (Pysde).
  This is my code :</p>
  
  <pre><code>import sys
  from PySide.QtCore import *
  from PySide.QtGui import *
  from PySide import QtGui,QtCore
  
  class Form(QtGui.QWidget):
  
      def __init__(self,parent=None):
          super(Form,self).__init__(parent)
  
          self.initUi()
  
      def initUi(self):
          self.setGeometry(300, 300, 800, 600)
          self.setWindowTitle('Library')
          self.setMinimumHeight(600)
          self.setMinimumWidth(800)
          self.setMaximumHeight(600)
          self.setMaximumWidth(1100)
  
          #Groupbox Show Only
          gpShowonly = QtGui.QGroupBox("Show only :")
          gpShowonly.setGeometry(100,100,200,200)
          chbx1 = QtGui.QCheckBox("x1")
          chbx2 = QtGui.QCheckBox("x2")
          chbx3 = QtGui.QCheckBox("x3")
  
          serverlayout = QtGui.QHBoxLayout()
  
          serverlayout.addWidget(chbx1)
          serverlayout.addWidget(chbx2)
          serverlayout.addWidget(chbx3)
  
          configLayout = QtGui.QVBoxLayout()
  
          configLayout.addLayout((serverlayout))
          gpShowonly.setLayout(configLayout)
  
          mainLayout = QtGui.QVBoxLayout()
          mainLayout.addWidget(gpShowonly)
          mainLayout.addStretch(1)
  
  
          self.setLayout(mainLayout)
          self.show()
  
  app = QApplication.instance()
  if app is None:
      app = QApplication(sys.argv)
  form = Form()
  form.show()
  app.exec_()
  </code></pre>
  
  <p>I want it's smaller but it's always full horizontal , I use setGeometry,resize but nothing happen.</p>