Neal Becker wrote:

I've recently seen problems where colors are totally wrong on some apps. First it was matplotlib. Now I see it on tortoisehg. Both I believe are QT5. Any ideas?

Yes, it is QT5 that causes the problem. If I switch matplotlib to Qt4agg backend, colors are fixed.

This is fedora f27 client + server. x2goclient-4.1.1.0-1.fc27.x86_64 2goserver-4.0.1.20-5.fc27.x86_64