I found this is similar issue like in bug #1761606. This issue I have in Lubuntu 18.04.5 installed on my hard drive. Like you said Lubuntu 18.04.5 is EOL now so this bug probably will be not fixed.
I have question. If I will install LXDE metapackage on focal this mean that lxpanel have still support and this bug can be fixed on focal package for LXDE environment?
I found this is similar issue like in bug #1761606. This issue I have in Lubuntu 18.04.5 installed on my hard drive. Like you said Lubuntu 18.04.5 is EOL now so this bug probably will be not fixed.
I have question. If I will install LXDE metapackage on focal this mean that lxpanel have still support and this bug can be fixed on focal package for LXDE environment?