Updates the tree view scrolling to the inputed value.
        
        :param      value | <int>

def _scrollTree( self, value ):
        """
        Updates the tree view scrolling to the inputed value.
        
        :param      value | <int>
        """
        if self._scrolling:
            return
        
        tree_bar = self.uiGanttTREE.verticalScrollBar()
        self._scrolling = True
        tree_bar.setValue(value)
        self._scrolling = False