'Start the tree from the first ancestor of requested comment.'

def get_initial_candidates(self, comment_tree):

    path = self.get_path_to_comment(self.comment, self.context, comment_tree)
    root_comment = path[0]
    initial_candidates = [root_comment]
    offset_depth = comment_tree.depth[root_comment]
    return (initial_candidates, offset_depth)
