title: PyQt QTreeview not displaying first column of QAbstractItemModel when built with Qt Designer
body: <p>I have built a <code>Tree</code> with <code>QAbstractItemModel</code> and test it with the code:</p>
  
  <pre><code>tree = TreeItem()
  app = QtGui.QApplication(sys.argv)
  app.setStyle("plastique")
  model = TreeModel(tree)
  treeView = QtGui.QTreeView()
  treeView.show()
  treeView.setModel(model)
  </code></pre>
  
  <p>The creted <code>tree</code> is correct (shown in figure below).</p>
  
  <p><img src="https://i.stack.imgur.com/4wLQU.png" alt="enter image description here"></p>
  
  <p>When I try to use the <code>Tree</code> in my application in <code>QTreeVeiw</code>, built with <code>Qt Designer</code> it only shows the second column - <code>Typeinfo</code> (shown in figure below). Actually the first column is not seen at the begining, but then if I pull the left edge of column <code>Typeinfo</code> to the right the first column is shown, but there are no <code>tree</code> lines displayed.</p>
  
  <p><img src="https://i.stack.imgur.com/TtBy0.png" alt="enter image description here"> </p>
  
  <p>With the code below, the <code>TreeView</code> is created:</p>
  
  <p><strong>tree_view_widget.py</strong></p>
  
  <pre><code>class TreeViewWidget(QMainWindow):
      def __init__(self, tree=None, parent=None, flags=0):
          super(TreeViewWidget, self).__init__(parent)
          self.ui = Ui_Form()
          self.ui.setupUi(self)
          model = TreeModel(tree)
          self.ui.treeView.setModel(model)
  </code></pre>
  
  <p><strong>tree_view_widget_ui.py</strong></p>
  
  <pre><code>class Ui_Form(object):
      def setupUi(self, Form):
          Form.setObjectName(_fromUtf8("Form"))
          Form.setEnabled(True)
          Form.resize(200, 300)
          Form.setMinimumSize(QtCore.QSize(200, 300))
          self.gridLayout = QtGui.QGridLayout(Form)
          self.gridLayout.setMargin(0)
          self.gridLayout.setHorizontalSpacing(0)
          self.gridLayout.setObjectName(_fromUtf8("gridLayout"))
          self.treeView = QtGui.QTreeView(Form)
          self.treeView.setEnabled(True)
          font = QtGui.QFont()
          font.setKerning(False)
          self.treeView.setFont(font)
          self.treeView.setFrameShadow(QtGui.QFrame.Sunken)
          self.treeView.setLineWidth(1)
          self.treeView.setMidLineWidth(0)
          self.treeView.setAutoScrollMargin(16)  # 16
          self.treeView.setTabKeyNavigation(True)
          self.treeView.setDragEnabled(True)
          self.treeView.setDragDropOverwriteMode(True)
          self.treeView.setDragDropMode(QtGui.QAbstractItemView.DragDrop)
          self.treeView.setAutoExpandDelay(-1)
          self.treeView.setIndentation(0)
          self.treeView.setRootIsDecorated(False)
          self.treeView.setUniformRowHeights(True)
          self.treeView.setSortingEnabled(True)
          self.treeView.setAnimated(False)
          self.treeView.setAllColumnsShowFocus(True)
          self.treeView.setHeaderHidden(False)
          self.treeView.setObjectName(_fromUtf8("treeView"))
          self.treeView.header().setDefaultSectionSize(0)
          self.treeView.header().setHighlightSections(False)
          self.treeView.header().setSortIndicatorShown(True)
          self.gridLayout.addWidget(self.treeView, 0, 0, 1, 1)
  
          self.retranslateUi(Form)
          QtCore.QMetaObject.connectSlotsByName(Form)
  
      def retranslateUi(self, Form):
          Form.setWindowTitle(_translate("Form", "Tree View", None))
  </code></pre>