Feature request: distinguish niced CPU time with a different color

It would be useful if CPU Graph could optionally display CPU time spent by niced processes in a different color.

Currently, the graph shows total CPU utilization, but there is no visual distinction between CPU time consumed by ordinary tasks and CPU time consumed by tasks running with a positive nice value. Having a separate color for the latter would make it much easier to tell whether a CPU core is being heavily used by normal workloads or by lower-priority background work.

For example, if a core is at 100% utilization, it could be displayed as something like:

• 70% normal CPU usage
• 30% niced CPU usage

On Linux, /proc/stat already provides a separate nice CPU-time counter, so I believe the information required to implement this is already available to the plugin.

This could perhaps be implemented as an optional color mode, with a user-configurable color for niced CPU time.

I vaguely remember seeing a similar visualization in another desktop environment/system monitor, possibly IceWM, although I may be remembering that incorrectly.

Linux exposes per-CPU user and nice CPU-time counters through /proc/stat, so it should be possible to distinguish niced CPU time on each logical CPU without per-process accounting.