Initialzes this item with a grouping style option.

def initGroupStyle(self, useIcons=True, columnCount=None):
        """
        Initialzes this item with a grouping style option.
        """
        flags      = self.flags()
        if flags & QtCore.Qt.ItemIsSelectable:
            flags ^= QtCore.Qt.ItemIsSelectable
            self.setFlags(flags)
        
        if useIcons:
            ico        = QtGui.QIcon(resources.find('img/treeview/triangle_right.png'))
            expand_ico = QtGui.QIcon(resources.find('img/treeview/triangle_down.png'))
            
            self.setIcon(0, ico)
            self.setExpandedIcon(0, expand_ico)
        
        palette = QtGui.QApplication.palette()
        
        line_clr = palette.color(palette.Mid)
        base_clr = palette.color(palette.Button)
        text_clr = palette.color(palette.ButtonText)
        
        gradient = QtGui.QLinearGradient()
        
        gradient.setColorAt(0.00, line_clr)
        gradient.setColorAt(0.03, line_clr)
        gradient.setColorAt(0.04, base_clr.lighter(105))
        gradient.setColorAt(0.25, base_clr)
        gradient.setColorAt(0.96, base_clr.darker(105))
        gradient.setColorAt(0.97, line_clr)
        gradient.setColorAt(1.00, line_clr)
        
        h = self._fixedHeight
        if not h:
            h = self.sizeHint(0).height()
        if not h:
            h = 18
        
        gradient.setStart(0.0, 0.0)
        gradient.setFinalStop(0.0, h)
        
        brush = QtGui.QBrush(gradient)
        
        tree = self.treeWidget()
        columnCount = columnCount or (tree.columnCount() if tree else self.columnCount())

        for i in range(columnCount):
            self.setForeground(i, text_clr)
            self.setBackground(i, brush)