KDE 4 got off to a slow start. Version 4.0 offered significant revisions under the hood, but the end user features still needed some polishing. Many users were disappointed with version 4.0, which was intended primarily for developers. Versions 4.1 and 4.2 were suitable for daily use, but KDE fans still had to do without a number of the features offered with KDE 3.

Version 4.3, alias Caizen, brings KDE 4 back to calmer waters [1]. Caizen refers to a Japanese philosophy of gradual or continuous improvement (Kaizen) [2].

Installation

Many distributions offer ready-to-run packages for KDE 4.3. Users of openSUSE can go to the KDE page [3] and install the necessary packages through YaST. Be sure to accept the signature keys for the new packages. To resolve a couple of conflicts manually, select openSUSE Build Service as the provider for Qt 4.5.2 and most other packages.

Packages for Kubuntu are available in the Kubuntu Backports PPA (Personal Package Archive). To add the required package source, use KPackageKit (Settings | Edit Software Sources at Third Party Software) or your favorite editor:

deb http://ppa.launchpad.net/kubuntu-ppa/backports/ubuntu jaunty main

From the this page link on the Kubuntu PPA Keys page [4], download the matching key. In Authentication, select Import Key File… to add the key. In the file dialog, make sure you change to your home directory and type * as the filter to locate the key file. Alternatively, type:

sudo apt-key adv --keyserver keyserver.ubuntu.com --recv-keys 8AC93F7A

The installation then occurs at the command line with:

sudo aptitude update ; sudo aptitude full-upgrade

The minimum installation for the Debian Unstable branch is the kde-minimal [5] package. If you prefer the complete KDE desktop, you additionally need to install kde-full. Users with Debian Testing, alias Squeeze, will have to wait, and backports for Debian Lenny are unknown as of this writing.

Plasma on Air

KDE 4.3 uses the lighter, brighter Air as the new default theme. If you prefer the Oxygen theme, you can right-click the desktop and select it.

The Plasma desktop shell comes with a plethora of new features. You can add various plasmoid applets to workspaces to define what are referred to as activities. Spacers give you more flexibility for designing panels, and you can move plasmoids wherever you like. For example, you can move a large plasmoid from the desktop to the panel; clicking the plasmoid will then open an extender.

New and improved plasmoids simplify daily desktop tasks. The new Bubblemon load monitor uses a glass sphere, filled to a greater or lesser extent, to indicate system CPU and memory load. (In our lab, the sensor caused an unusually high level of CPU activity, so be careful when you scale up the sphere.) Other sensors display battery charge state, CPU frequency and load, and RAM statistics.

The new openDesktop plasmoid makes it easier to find other KDE users in your neighborhood, but first you need an account with openDesktop.org, the umbrella organization for KDE-Look.org, Gnome-Look.org, and other desktop-related community websites. The plasmoid uses the GeoLocation service to discover KDE users in your neighborhood. The Register button uses an unencrypted HTTP connection to open the website with the registration form. Changing the URL in your browser to https to encrypt your data is a good idea. Unfortunately, the applet also uses unencrypted connections internally. This issue was resolved in the new developer branch; KDE 4.3.1 will use HTTPS by default.

The Remember the Milk task planner gadget also interacts with an online service and uses unencrypted HTTP. The applet crashed fairly frequently in our lab. It might be a good idea to wait for a bug fix before experimenting with Remember the Milk, because plasmoids run in the Plasma process context, and a single applet crashing can affect the desktop as a whole. (If Plasma fails to restart after a crash, you can restart manually by pressing Alt+F2 and entering plasma-desktop.)

The folder view displays a preview of the object below the mouse pointer; you can set the file types for which you need this functionality. In the case of directories, content is displayed, thus supporting fast, click-free navigation of the filesystem (Figure 1). The right-click menu contains entries for controlling the workspace. If you want to store a snippet of text for later use, select the text and press the middle button on the mouse to store the text as a notice on your desktop. If you click the T button, the Notice plasmoid gives you more formatting options. Additionally, Plasma now has animated wallpapers, such as Mandelbrot fractals, the Marble globe, or a virus that eats up the desktop (Figure 2).

The Desktop

The system area in the control panel groups messages that belong together and hides the messages after a while. If you want to receive notifications, you can choose to show messages from applications, from file transfers and other actions, or from all sources. Unfortunately, with a large number of messages, ungrouped messages had to be closed individually, and it was impossible to open the view if more than 30 or 40 messages were present. Sometimes, the system tray did not fully display messages.

Also, you can configure the icon categories to display in the system tray. The applet will only display some icons in an expanded state, which you define with Automatically hide in the settings. Additionally, the system tray offers a new framework for communicating with applications, designed to resolve issues in the previous approach. The KGpg key manager already uses this framework.

KDE's KRunner application launcher tool now displays elements in a list and provides explanatory text (Figure 3). The help features, accessible via the question mark icon, are useful. KRunner can find programs, recently used documents, Kate text editor sessions, browsed websites, file manager locations, Konqueror profiles, and many other things. Konqueror web shortcuts are also useful. To view or change a shortcut, enter Web shortcut.

The traditional KDE menu can show recently used applications and system preferences (Figure 4). The Klipper clipboard offers actions to match file names. From Enable clipboard actions in the Klipper context menu, you can enable and disable this practical, but somewhat pushy, function. Plans are to move this function to the background while retaining good accessibility.

The preferences reinstate the tree view so sorely missed by KDE 3 users. A module with settings for KDE's Solid hardware library lets you define actions for pluggable devices or insertable media.

The Dolphin file manager also has new functions. Thumbnail previews of image files become the icons for image directories in turn. The program also offers previews for audio and video files. In View | Sort by, you can specify whether Dolphin should show folders before files or mix the two.

The new desktop search in Dolphin relies on Nepomuk and the Soprano RDF framework and is useful (when it works), either through the search box or by typing nepomuksearch:/ as a URL. Soprano comes with the Reland C++/Qt4 back end, which didn't work consistently with any of the distros I tested. While the Debian KDE team waits for a usable back end [6], openSUSE and Ubuntu include the alternative Java-based Sesame back end in soprano-backend-sesame.

PolicyKit integration offers a standardized authorization mechanism for assuming privileges [7], although there is not much to see apart from the settings module right now. The idea is that programs that need root would launch a service that runs with root privileges and use PolicyKit to control access privileges for the service. PolicyKit is useful for tasks such as setting system preferences that need root privileges.