With or without space in "CPU%d" and "CPU %d"
"CPU%d" and "CPU %d" are written two ways (without and with space) in: https://gitlab.gnome.org/GNOME/gnome-system-monitor/-/blob/master/src/setaffinity.cpp#L407 https://gitlab.gnome.org/GNOME/gnome-system-monitor/-/blob/master/src/interface.cpp#L255
I think it should be written the same way both places. E.g. using the same string.
In the processes tab it says:
[colored box] CPU1 6.4%
So addeding a space after "CPU" will looks something like:
[colored box] CPU 1 6.4%
Which might not be nice since a number comes afterwards. But maybe something can be done to seperate "CPU 1" and "6.4%" in case a space is added. Memory and swap and network have the text on different lines. Perhaps CPU1 could be inside the colored box or be colored text.
[colored box] CPU 1
6.4%