Problems when group company-jedi with other backend about company-jedi HOT 7 OPEN

(require 'package)

(setq package-archives '(("marmalade" . "http://marmalade-repo.org/packages/")
                         ("gnu" . "http://elpa.gnu.org/packages/")
                         ("melpa" . "https://melpa.org/packages/")
                         ("org" . "http://orgmode.org/elpa/")))

(package-initialize)

(unless (and (file-exists-p (expand-file-name "elpa/archives/marmalade" user-emacs-directory))
             (file-exists-p (expand-file-name "elpa/archives/gnu" user-emacs-directory))
             (file-exists-p (expand-file-name "elpa/archives/melpa" user-emacs-directory))
             (file-exists-p (expand-file-name "elpa/archives/org" user-emacs-directory)))
  (package-refresh-contents))

(unless (package-installed-p 'use-package)
  (package-refresh-contents)
  (package-install 'use-package))

(require 'use-package)

(package-install 'company)
(package-install 'jedi-core)
(package-install 'company-jedi)

(require 'company)
(require 'jedi-core)
(require 'company-jedi)

(global-company-mode)
(add-hook 'python-mode-hook
          (lambda ()
            (setq company-backends '((company-jedi
                                      company-yasnippet ;; Comment out this line and the follow one should find some differences 
                                      company-files ;; 
                                      company-dabbrev-code
                                      company-gtags
                                      company-etags
                                      company-keywords)
                                     company-dabbrev))))

(custom-set-variables
 '(company-idle-delay nil))