Issues with tmux status bar on Ubuntu 20.04 LTS

[rstemmer]

cpubgline does not work inside the status bar of tmux on Ubuntu 20.04 LTS.
When the status bar tool calls cpubgline, it has always a different parent ID so that cpubgline cannot build up a history to calculate the CPU usage delta between the current and previous call.

Since it works fine on Arch linux and I do not care about Debian/Ubuntu I will not address this issue.
This ticket is more a "For Your Information" post 😀

Of cause everybody is welcome to address and fix this issue. I may address it when it stops working on Arch linux.