def SetHighlight( self, node, point=None, propagate=True ):
        """Set the currently-highlighted node"""
        if node == self.highlightedNode:
            return
        self.highlightedNode = node
        # TODO: restrict refresh to the squares for previous node and new node...
        self.UpdateDrawing()
        if node and propagate:
            wx.PostEvent( self, SquareHighlightEvent( node=node, point=point, map=self ) )
Set the currently-highlighted node