I have a triple monitor setup configured where all three monitors are arranged horizontally in a row. After any reboot, all configuration is lost and the monitors are setup as clones. I can occasionally rearrange them, but the placement and configuration of my panels are then very broken and getting them back into place is an exercise in futility. Reproducible: Always Steps to Reproduce: 1. Arrange displays 2. Reboot 3. n/a Actual Results: Display configuration is lost and all monitors are reset to default as clones Expected Results: Display configuration is retained and I don't lose hours of my work day trying to get things back into working order. Trying to fix the placement of panels, or add new panels, on multi-monitor systems is rage inducing. This is absolutely something you guys need to get right -- this is the foundation on which all usability for the desktop sits. If it's as broken as it is, I can't imagine many will stick around and silently deal with it.
A similar issue here with Kubuntu 16.04.3 and plasma 5.5.5. I have 3 displays oriented vertically (rotate 90° left). After reboot the first 2 screens are horizontal and on top of each other with an offset, the 3rd screen is oriented and positioned correctly. It looks like KDE corrupts my display setup on reboot and sometimes on re-login. Is there a work-around for this issue please?
Plasma 5.5 is no longer maintained, please ask in a forum of your distribution how to install recent KDE software. The minimum supported versions are Plasma 5.8 LTS, Plasma 5.11, or the new Plasma 5.12 LTS. If you can still reproduce with a recent version, please add a comment.