ayatana-indicator-sound misses playback control (Previous, Play, Next) buttons

[Norbert]

Steps to reproduce:

1. Install any Ubuntu MATE version which ships ayatana-indicator-sound - 20.10, 21.04 or upcoming 21.10
2. Launch preinstalled Rhythmbox player, select any internet Radio station to play
3. Open ayatana-indicator-sound by clicking on volume button

Expected results:

* ayatana-indicator-sound shows the following interface elements - artist, song name, Previous, Play, Next control buttons as it shown on screenshot below from Ubuntu MATE 20.04 LTS (https://user-images.githubusercontent.com/309456/130291599-92e5ff43-2d4c-4b6f-b159-1cced32e7bd9.png)

Actual results:

* ayatana-indicator-sound shows only artist and song name as shown on screenshot below from Ubuntu MATE 20.10 (https://user-images.githubusercontent.com/309456/130291912-a53ea7a8-314d-45f2-8ce0-bb02556f7715.png)

Note: the same happens in the latest Ubuntu MATE 21.10 (development branch).

ProblemType: Bug
DistroRelease: Ubuntu 20.10
Package: ayatana-indicator-sound 0.8.0-1
ProcVersionSignature: Ubuntu 5.8.0-63.71-generic 5.8.18
Uname: Linux 5.8.0-63-generic x86_64
ApportVersion: 2.20.11-0ubuntu50.7
Architecture: amd64
CasperMD5CheckResult: skip
CurrentDesktop: MATE
Date: Fri Aug 20 23:48:18 2021
InstallationDate: Installed on 2021-08-20 (0 days ago)
InstallationMedia: Ubuntu-MATE 20.10 "Groovy Gorilla" - Release amd64 (20201022)
SourcePackage: ayatana-indicator-sound
UpgradeStatus: No upgrade log present (probably fresh install)

[Norbert (nrbrtx)]

Upstream bug-report - https://github.com/AyatanaIndicators/ayatana-indicator-sound/issues/28 .

[Norbert (nrbrtx)]

The same happens with other media players like VLC, SMPlayer from official repositories and Guayadeque from PPA ( https://launchpad.net/~anonbeat/+archive/ubuntu/guayadeque ) .

Maybe it is dependency issue.

[Martin Wimpress  (flexiondotorg)]

I can not reproduce this in Ubuntu MATE 22.04 daily.