KDE

KDE Plasma is a desktop environment that aims to be simple by default, powerful when needed.

Installation

To use KDE Plasma, add this to your configuration.nix:

services.xserver.enable = true;
services.xserver.displayManager.sddm.enable = true;
services.xserver.desktopManager.plasma5.enable = true;
# services.xserver.desktopManager.plasma6.enable = true; # KDE6 available on unstable

Excluding some KDE Plasma applications from the default install

Not all applications that come pre-installed with the KDE Plasma desktop environment are desirable for everyone to have on their machines. There's a way to edit configuration.nix to exclude some optional packages, for example as follows:

environment.plasma5.excludePackages = with pkgs.libsForQt5; [
  plasma-browser-integration
  konsole
  oxygen
];

Configuration

GNOME desktop integration

Using the following example configuration, QT applications will have a look similar to the GNOME desktop, using a dark theme

qt = {
  enable = true;
  platformTheme = "gnome";
  style = "adwaita-dark";
};

Troubleshoots

Qt/KDE applications segfault on start

This is caused by a stale QML cache (see this issue). A dirty way to fix this is by running on a terminal the following command:

find ${XDG_CACHE_HOME:-$HOME/.cache}/**/qmlcache -type f -delete

GTK themes are not applied in Wayland applications / Window Decorations missing / Cursor looks different

This affects GTK applications including Firefox and Thunderbird.

Add to your configuration.nix the following line:

programs.dconf.enable = true;

You might also need to set a GTK theme Breeze imitating the KDE theme with the same name in System Settings -> Application Style -->Configure GNOME/GTK Application Style.

(See this issue)

KMail Renders Blank Messages

When you see the message grantlee.template: "Plugin library 'kde_grantlee_plugin' not found." and/or kmail does shows only empty message then add to your configuration.nix the following line:

environment.sessionVariables = {
  NIX_PROFILES = "${pkgs.lib.concatStringsSep " " (pkgs.lib.reverseList config.environment.profiles)}";
};

(See this issue)

Launch KDE in Wayland session

services.xserver.displayManager.defaultSession = "plasmawayland";

Launch SDDM in wayland too

It's possible to launch sddm in wayland too to try to avoid running an X server.

services.xserver.displayManager.sddm.wayland.enable = true;

Plasma-Manager

Note: Plasma-Manager is not matured yet and currently unofficial

On default the plasma configuration can be handeld like on traditional systems. With plasma-manager it is possible to make plasma configurations via nix by providing home-manager modules.