Hi!
The current 3.8.1 coloring is the “Christinas Edition” which will be reverted to the normal colors in the next Release. If you don’t want to wait you can use the current dev builds from https://builds.jabref.org/master
However, I’ll consider adding a preference option to allow customizing the colors of enabled/disabled Icons.
I am color blind and the current red/green schema puts a lot of cognitive strain on me, because the colors are barely distinguishable for me. The old menu schema was much better. Reversion to the old schema or an option to configure the color schema will solve this.
Sorry for this inconvenience. The current red/green color scheme was just a small gag for a “christmas edition” of JabRef.
The next released version will be in the “normal” color scheme again - and as pointed out above you can just use the current developments builds with the normal colors.
You find the new configuration possibilities in Options -> Preferences -> Appearance.
Disclaimer: We are currently moving to JabRef 4.0.0 which will partially be using another UI technology (JavaFX). Thus, some features might not exactly behave as before and as expected. So please backup your data (and settings) before trying out the dev build.