Dual setup - 2nd screen portrait doesn't work properly (RX570 - U3818dw & U3417dw)

[pixelwm]

Hi,

I just got a Dell U3818dw screen in addition to my U3417dw one and ran into a funny problem.

Both screens get detected and work, but when I rotate the 2nd screen to portrait in the settings, the first
one gets smaller and mirrored to the second.

I have an ATI RX 570. The card def. can run the screens (one landscape, the other portrait), tested
it with an Ubuntu distribution.

Has anyone ran into a similar problem?

(I tried RadeonDeinit switch, WhatEverGreen + Lilu and all available frame buffers in clover)

Best,
Markus

[pixelwm]

Just figured it out. You have to select "Show mirroring options in the menu bar when available" in the System Preferences and then select "Use as seperate displays" from the menu bar icon.