Hey there, I've had an issue since updating to 1.12.1 where it was not present in 1.12 for me. When selecting an area, the cuboid first point color (green) is also the cuboid second point color (meant to be blue according to default config, but appears green). I've not touched the config colors and the ingame worldeditcui options page shows the second point as blue.
Client loaded with Forge 2444 and mods:
First bug report so if theres a log you require, let me know what/where and I'll pastebin it for you.