Menus that fill themselves on QMenu::aboutToShow don't work

Example application

Status changed to 'Confirmed' because the bug affects multiple users.

This bug was fixed in the package unity8 - 8.15+17.04.20170321-0ubuntu1

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unity8 (8.15+17.04.20170321-0ubuntu1) zesty; urgency=medium

  [ Albert Astals Cid ]
  * Signal aboutToShow (LP: #1664578)
  * Support Panel top level items to be disabled (LP: #1670694)
  * Improve Launcher ←→ touch menu interaction (LP: #1667620, #1671069)
  * Fix real world submenus (e.g. kate) not getting their first item
    selected on open (LP: #1666859)

  [ Daniel d'Andrada ]
  * Really disable the window decoration when in staged mode (LP:
    #1670361)
  * Don't let clients resize their surfaces while in staged
    (phone/tablet) mode (LP: #1670390)
  * TopLevelWindowModel: don't put hidden windows in the model (LP:
    #1665286)

  [ Lukáš Tinkl ]
  * Reset always-show-osk gsetting on startup to default value (false
    atm)
  * Fix the restored-to position with Miral due to the state changes
    being async (LP: #1669819)
  * Add a cursor name fallback mapping "grabbing" -> "closedhand" for
    Breeze
  * Fix unsnapping a maximized window from the panel (LP: #1671721)
  * Disable altDrag feature outside windowed mode

  [ Michael Terry ]
  * Don't lock the screen for guest users or users in the nopasswdlogin
    group. (LP: #1644237)
  * Support GNOME-style logout DBus API (making the Logout, Reboot, and
    Shutdown launcher commands work) (LP: #1673229)

  [ Michael Zanetti ]
  * Add support for closing apps from the spread with "Q" (LP: #1670327)
  * hide "private" launcher quicklist entries when the greeter is locked
    (LP: #1667649)
  * add surface titles to launcher's quicklist (LP: #1661668)
  * properly reset the drawer state when cancelling a horizontal drag
    (LP: #1669536)
  * fix the focus moving correctly between launcher and drawer (LP:
    #1669880)
  * unfocus the drawer's textfield when it is moved (LP: #1669839)

  [ Pete Woods ]
  * Fix up indicators-client after refactoring (LP: #1672797)

 -- Michał Sawicz <email address hidden> Tue, 21 Mar 2017 10:58:13 +0000

This bug was fixed in the package qtubuntu - 0.64+17.04.20170320-0ubuntu1

---------------
qtubuntu (0.64+17.04.20170320-0ubuntu1) zesty; urgency=medium

  [ Albert Astals Cid ]
  * Set qtubuntu-tag and handle aboutToShow calls (LP: #1664578)
  * Set enabled state for menus in the submenu-enabled property since
    GMenuModel doesn't support that concept (LP: #1670694)
  * fix image conversion to Format_ARGB32
  * Build with clang

  [ Gerry Boland ]
  * Use correct parented/parentless dialog and utility window types from
    Mir

 -- Lukáš Tinkl <email address hidden> Mon, 20 Mar 2017 17:31:42 +0000