That's a weird issue. I already have it set to do exactly that. Any message s with log level WARN are shown in yellow, while any message with a log level ERROR or FATAL is shown in red. See pic:
https://i.imgur.com/Ph4Vdef.png
What messages aren't being shown in the right color? Please post them in the discussion tab so I can take a look at it.
Version: v1.5.3-ALPHA
Very nice plugin, it's not what I usually see but it's a nice concept! Keep up the good work :)