:keyboard-post-menu and editor pane

Hello lispworkers,

I try to pop-up a menu by means of the keyboard inside an interface of my
own. I display the pane:

(capi:contain (make-instance 'capi:editor-pane :title "My pane:"))

On clicking :button-3 (the right button on Windows), a standard menu is
displayed. But pressing Shift-F10 only activates the a menu bar -
the context menu does not appear.

Neither the redefinition helps...

(defmethod capi:pane-popup-menu-items ((pane capi:editor-pane) (interface capi:interface))
  `(,(make-instance 'capi:menu-item :title "One")
    ,(make-instance 'capi:menu-item :title "Two")))

.... nor adding the gesture

(capi:contain (make-instance 'capi:editor-pane :title "My pane:"
          :input-model (cons '(:keyboard-post-menu my-post-menu)
                                           CAPI::*EDITOR-INPUT-MODEL*)))

I wonder how Shift-F10 works in the Editor tool and the Listener in LWW4.4
and LWW5.0. Does anybody know the secret?
--
Sincerely,
Dmitriy Ivanov
lisp.ystok.ru