KDE (desktop environment)

Installation

Prior to R3.2, KDE was the default desktop environment in Qubes. Beginning with R3.2, however, XFCE is the new default desktop environment. Nonetheless, it is still possible to install KDE by issuing this command in dom0:

$ sudo qubes-dom0-update kde-settings-qubes

You may notice some warnings and errors in the installation - it is safe to ignore these.

After the installation is complete log out. At the top of the log in screen is a small icon with X on it - if you click on it you will see choices between Xfce and Plasma. Select the Plasma(X11) option, and log in - you will see that Plasma (the KDE desktop environment) loads.

KDE is very customisable, and there is a range of widgets to use. If you want to use the Menu widget, then you must edit /etc/X11/xinit/xinitrc.d/55xfce-qubes.sh as follows:

#!/usr/bin/sh

# Use Qubes provided menu instead of default XFCE one
if [ "$XDG_SESSION_DESKTOP" = "KDE" ]; then
XDG_MENU_PREFIX="kf5-"
else
XDG_MENU_PREFIX="qubes-"
fi
export XDG_MENU_PREFIX

This allows you to edit the menu as you will. When editing the Menu DO NOT use the option under “Edit->Restore to System Menu”

Login manager

You can also change your default login manager (lightdm) to the new KDE default: sddm

  • first you need to edit the /etc/sddm.conf to make sure if the custom X parameter is set according to Qubes needs:

     [XDisplay]
 ServerArguments=-nolisten tcp -background none

  • disable the lightdm service:

     $ sudo systemctl disable lightdm

  • enable the sddm service:

      $ sudo systemctl enable sddm

  • reboot

If you encounter performance issues with KDE, try switching back to LightDM.

Window Management

You can set each window’s position and size like this:

Right click title bar --> More actions --> Special window settings...

  Window matching tab
    Window class (application): Exact Match: <vm_name>
    Window title: Substring Match: <partial or full program name>

  Size & Position tab
    [x] Position: Apply Initially: x,y
    [x] Size: Apply Initially: x,y

You can also use kstart to control virtual desktop placement like this:

  kstart --desktop 3 --windowclass <vm_name> -q --tray -a <vm_name> '<run_program_command>'

(Replace “3” with whichever virtual desktop you want the window to be on.)

This can be useful for creating a simple shell script which will set up your workspace the way you like.

Removal

If you decide to remove KDE do not use dnf remove @kde-desktop-qubes. You will almost certainly break your system.

The safest way to remove (most of) KDE is:

sudo dnf remove kdelibs plasma-workspace