Window List menus on MATE Panel do not have up and down scroll buttons on low screen resolutions or with long lists

[Norbert]

Steps to reproduce:
1. Have Ubuntu 18.04 LTS (or newer) installed
2. Change screen resolution to minimal - it is easy on VM
3. Open some window and make right click on its button on Window List applet of down MATE Panel

Expected results:
* drop down window menu has scroll buttons (see screenshot "1604-down.png")

Actual results:
* drop down window menu does not have scroll buttons and looks non-intuitive (see screenshot "1804-down.png")

ProblemType: Bug
DistroRelease: Ubuntu 18.04
Package: mate-panel 1.20.1-3ubuntu1
ProcVersionSignature: Ubuntu 4.15.0-43.46-generic 4.15.18
Uname: Linux 4.15.0-43-generic x86_64
ApportVersion: 2.20.9-0ubuntu7.5
Architecture: amd64
CurrentDesktop: MATE
Date: Sun Feb 3 09:49:09 2019
InstallationDate: Installed on 2018-04-26 (282 days ago)
InstallationMedia: Ubuntu-MATE 18.04 LTS "Bionic Beaver" - Release amd64 (20180426)
SourcePackage: mate-panel
UpgradeStatus: No upgrade log present (probably fresh install)

[Norbert (nrbrtx)]

Modern releases as 18.10 and 19.04 are affected too.

[Launchpad Janitor (janitor)]

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

[Norbert (nrbrtx)]

Looks good in 21.10.