You change your configuration but the screen is always mirrored
Most of the time this happens when you boot with one screen in the off status
You need to delete the following file in your home directory:
This file should be deleted and afterwards you can reconfigure. After the reconfiguration, the settings will be correct and stay after reboot.
Please note that this solution is probably "Kubuntu version" specific.
About the Author
Wim Peeters is electronics engineer with an additional master in IT and over 30 years of experience, including time spent in support, development, consulting, training and database administration. Wim has worked with SQL Server since version 6.5. He has developed in C/C++, Java and C# on Windows and Linux. He writes knowledge base articles to solve IT problems and publishes them on the Lubby Knowledge Platform.