I see! So basically you start plasma from the xfce4. I thought you started the plasma_session without the xfce4. I just have tried this way and worked me too. However, I still have the xfce4 menu bars (top and bottom ones) are still available and the scaling is not quite right. Here is the result: https://i.ibb.co/9WnZ3VR/plasma-on-treltexx1024.png For the landscape mode, I would suggest to start xfce4 in landscape first. Plus, to be able to launch the Chromium browser, you don't need to start plasma. I just installed Chromium and was able to launch from the menu within xfce4 without plasma_desktop. I'll play with plasma. It would be good if plasma somehow can be started as a default DE.