USB-C dock

[Arwen]

Thank you, flipping the usb cable helped, though on my smartphone it worked both ways. 

I noticed some strange effect after connecting the second monitor (see the picture attached), sort of graphic lag. Is it because two monitors are too "heavy" for my pinebook?

Great.

It's possible as time goes on, we won't have that USB C cable polarity issue. The low level device is suppose to be able to handle it either way. But, it may take time for kernel developers to make auto-configuration work properly.

As for the graphic lag, I don't know. Our Pinebook Pros do not contain the fast graphics. More than enough for normal use. It's possible that the kernel you are using does not have all the GPU acceleration enabled. I don't have a good way to verify that right now. Whence we do, (for all kernels and the various graphic modules), we can add it to the Pinebook Pro Wiki site for trouble shooting.