XFCE4-panel and conky flicker strongly with VBox 3D accelleration

[BertN45]

The panel and the conky display flicker very strongly during many operations, but especially during the whole process of using the software-updater. Only xubuntu has the problem, ubuntu, kubuntu. lubuntu, ubuntu-mate and ubuntu-budgie have no problem.
It only happens when 3D acceleration is enabled in Virtualbox, I had no problem with Ubuntu 18.04. The problem also occurs in a fresh install.

In 2018 I moved all my activities to VMs and Xubuntu is the VM for all office related activities.

ProblemType: Bug
DistroRelease: Ubuntu 20.04
Package: xfce4-panel 4.14.3-1
ProcVersionSignature: Ubuntu 5.4.0-14.17-generic 5.4.18
Uname: Linux 5.4.0-14-generic x86_64
ApportVersion: 2.20.11-0ubuntu20
Architecture: amd64
CurrentDesktop: XFCE
Date: Thu Mar 12 12:26:46 2020
InstallationDate: Installed on 2018-03-11 (732 days ago)
InstallationMedia: Xubuntu 18.04 LTS "Bionic Beaver" - Alpha amd64 (20180310)
SourcePackage: xfce4-panel
UpgradeStatus: Upgraded to focal on 2020-03-04 (7 days ago)