The "Add to Favorites" is not shown for some Qt(?) applications in dash/dock

[Norbert]

Steps to reproduce:
1. Install Ubuntu 18.04 LTS
2. Install Kate (or Gwenview, Dolphin)
3. Launch Kate (or Gwenview, Dolphin) from 9-dots-menu
4. Try to pin the application to the dash/dock with "Add to Favorites" option

Expected results:
* the "Add to Favorites" is shown in the menu for all applications

Actual results:
* the "Add to Favorites" is not shown in the menu for all applications

Notes:

1. first seen on AskUbuntu ( https://askubuntu.com/q/1166171/66509 ).
2. pinning to dock works as expected in Unity and MATE (using Mutiny panel layout).

ProblemType: Bug
DistroRelease: Ubuntu 18.04
Package: gnome-shell 3.28.4-0ubuntu18.04.1
ProcVersionSignature: Ubuntu 4.15.0-58.64-generic 4.15.18
Uname: Linux 4.15.0-58-generic x86_64
ApportVersion: 2.20.9-0ubuntu7.7
Architecture: amd64
CurrentDesktop: ubuntu:GNOME
Date: Fri Aug 16 17:20:39 2019
DisplayManager: lightdm
GsettingsChanges:
 b'org.gnome.shell' b'command-history' redacted by apport
 b'org.gnome.shell' b'favorite-apps' redacted by apport
 b'org.gnome.desktop.interface' b'gtk-im-module' b"'gtk-im-context-simple'"
InstallationDate: Installed on 2018-04-26 (476 days ago)
InstallationMedia: Ubuntu-MATE 18.04 LTS "Bionic Beaver" - Release amd64 (20180426)
SourcePackage: gnome-shell
UpgradeStatus: No upgrade log present (probably fresh install)

[Launchpad Janitor (janitor)]

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