I have a lot of flickering or blinking here and there not only in a browser in macOS. And last firefox is the only browser that doesn't have this problem.
In Mavericks there are some graphic artifacts in dock also sometimes but don't so much as in higher os versions.
Vmware 12/14. Guest OS: 10.9-10/13. Graphics card: Nvidia.
I'm remember that there was absolutely no artifacts in Mavericks before as it doesn't heavily relies on 2d/3d acceleration as Yosemite+.
So the problem lies in a newer version of Vmware or it's a problem with the settings in Vmware/Nvidia drivers?