You may use Hardcode-Tray to fix the issue with colourful tray icons. Currently it supports only the Numix and Papirus icon themes (actually, you can manage any icon icon theme to work with Hardcode-Tray, see below1).
You can use whatever theme you like as soon as the theme supports the app you want to fix. We detect which icons the theme has and get the ones we need for each app. so if you create a new theme called for example "Test" with the icons you need, you can use that by passing --theme argument. You don't need to use that theme in order to use it to fix your hardcoded icons, you can use whatever theme you like, if the colors doesn't match your color, we have already an argument to change the colors during the process too.
You may use Hardcode-Tray to fix the issue with colourful tray icons. Currently it supports only the Numix and Papirus icon themes (actually, you can manage any icon icon theme to work with Hardcode-Tray, see below1).
You can install it from a PPA by running
Then run
hardcode-tray
byand it will give you an option to "fix" the tray icons.