Last week, the KDE community officially released KDE Software Compilation 4.4, a significant update of the open source desktop environment and its associated application stack. The new version delivers some user interface improvements, enhanced usability, new features, additional software, and a number of important bug fixes.

Window management improvements

Window management is one area where users can find particularly noteworthy improvements in KDE SC 4.4. KDE's KWin window manager has new visual effects and functionality, including long-awaited support for window grouping. This feature makes it possible for users to combine their windows into tabbed groups for easier and more streamlined window management. In the following screenshot, you can see a terminal window, a file management window, and the Qassel IRC client tied together in a tab group. The grouped windows will move together and behave like a singular window entity.

Several windows combined into a tabbed group

Users can create a tab group by middle-clicking a window titlebar and dragging it over the titlebar of another window. You can also use the middle-click dragging method to break a window out of a tab group or to reorder the tabs within a group. KDE's Oxygen window decoration theme was augmented to accommodate the new tab feature. The tabs are displayed in combined titlebar that has a segment for each window in the group. When you are moving the tabs around within the titlebar, the Oxygen theme employs some subtle animated transitions to make the tab changes feel more natural.

Another great addition to KWin is support for desktop edge snapping, which makes it easy to maximize a window along one of the screen edges. This feature appears to be modeled after the popular Aero Snap feature that Microsoft introduced in Windows 7. You can maximize a window by dragging it to the top of the screen or you can tile two windows horizontally in a side-by-side arrangement by dragging them to the left and right screen edges.

Windows tiled with edge snapping in KDE SC 4.4

It's a nice feature, but I'd really like to see the developers take it to the next level by enabling richer tiling than a mere side-by-side view. Fortunately, there is a project under active development that could eventually introduce true Ion-style tiled window management to KWin with support for dynamic resizing. It's an ongoing effort and wasn't ready for inclusion in 4.4.

The virtual desktop grid effect, which shows a birds-eye view of the user's virtual desktops, got a really clever improvement in 4.4. When you activate the grid, it will also simultaneously activate the Expose-style Present Windows effect on all of the desktops so that you can see every single open window at a glance. When you drag a window from one desktop to another in the grid mode, it will automatically reorganize the thumbnails so that all of the windows are still visible.

Four virtual desktops displayed with the desktop grid feature

Nepomuk integration

KDE's Nepomuk search framework is more tightly integrated in KDE SC 4.4. One of the new features introduced on top of Nepomuk is the timeline file view, which makes it easy to see which files were used on a specific day. It uses KDE's KIO virtual filesystem framework, so it is integrated directly into the file manager and file dialogs. The idea was inspired by Zeitgeist, a GNOME project that is working to enable journal-like file management.

A Nepomuk-powered timeline view in the Dolphin file manager

Nepomuk made it trivially easy for a KDE developer to implement roughly comparable functionality. Because it's exposed through KIO, it acts just like a regular filesystem. You can descend into a "folder" for an individual date and see all of the files that were used on that day. KDE developer Sebastian Trug described the feature in a blog entry back in October.

Nepomuk also powers a new search interface that has been added to Dolphin. It allows you to perform granular searches on a number of different parameters. It takes advantage of KDE's Strigi service, which performs full-text indexing on a wide range of different types of documents. I didn't have much luck getting the search feature to work in Dolphin during my tests, but I suspect that the problems I encountered were due to distro integration issues. It's sometimes difficult to get the full KDE experience when you have to use an unreleased distro version.

Searching for files in the Dolphin file manager

There is a lot of really compelling technology being built on top of Nepomuk in the KDE ecosystem. The developers hope to use it to enable a semantic desktop, an environment in which meaningfully related data is linked together. On an abstract level, this could mean a lot of different things. In KDE, it's principally about leveraging file metadata to break down the walls between applications and different kinds of content—such as files, contacts, messages, and media.

This notion of a semantic desktop was a fundamental part of the KDE vision, but it has taken a long time for its practical value to rise to the surface. Nepomuk is finally reaching the requisite level of maturity to deliver on its promises. The timeline view is a pretty good example of how Nepomuk can radically simplify the development of functionality that has real-world usefulness.

The underlying technology behind Nepomuk represents years of work and millions of euros in development costs, a substantial portion of which was supplied by the European Union. It's arguably an important contribution to the advancement of modern computing. KDE users will be among the first to benefit from this research. For additional details about the ongoing effort to integrate Nepomuk in KDE, I recommend reading Trug's overview of the work on the project that took place in 2009.

Plasma improvements

KDE's Plasma desktop shell has continued to evolve. There are some nice usability improvements in this release, particularly a new widget manager. In previous versions of Plasma, the list of available widgets was displayed as a scrolling list in a dialog window. The new version has a widget organizer that can pop out of the Plasma panel container.

The Plasma widget organizer in KDE SC 4.4

The organizer, which looks a lot like the widget manager in Apple's Dashboard system, is a horizontal strip that displays large icons for each Plasmoid. You can drag a Plasmoid out of the strip and embed it in a panel or place it on the desktop. The organizer has filtering elements that you can click to view a subset of the widgets by category. You can also search and see a list of widgets that match your query.

New software and plasmoids

KDE's Social Desktop project, which was introduced in KDE 4.3, has advanced a bit in this release. The Social Desktop software uses KDE's OpenDesktop APIs to interact with KDE-Look.org and other popular websites in that network. The APIs are all open and documented with the aim of enabling third-party Web service providers to build compatible implementations. In KDE SC 4.4, the Social Desktop widgets have been updated. There is now a dedicated activity stream widget, which shows what your friends are doing on OpenDesktop-enabled sites.

The Plasma netbook shell, which we reviewed last year, has improved considerably. KDE SC 4.4 is the first version to tout the alternate netbook interface as an officially-supported option. The netbook interface allows users to arrange their Plasmoids in a "newspaper" layout that behaves like a flowing grid. It's an optimal view for netbooks and other small form-factor devices.

Distro notes

I tested KDE SC 4.4 on a prerelease daily build of the upcoming Kubuntu 10.04. Although I typically favor openSUSE as a reference distribution for KDE reviews due to its superior integration, I ran into a number of packaging issues when I attempted to install KDE SC 4.4 from openSUSE's build service. After several unsuccessful attempts to get it up and running, I fell back to Kubuntu, which worked without a hitch.

I don't typically discuss distro issues at length in KDE reviews, but I wanted to note that I'm increasingly satisfied with Kubuntu as a KDE distribution. It has, perhaps, overcome some of the early obstacles that prevented it from truly rivaling openSUSE and Mandriva as first-class KDE distributions. It's still not perfect for pre-release testing, but it got the job done.

For users who want to do hands-on testing with KDE SC 4.4 today, I can recommend it as one potential option. The openSUSE developers say that they will be making a live CD available soon that should supply a working 4.4 environment out of the box. If you want to test it with openSUSE, you are probably better off waiting for that rather than trying to dive in today with openSUSE Factory.

Conclusion

KDE has come a very long way since the initial 4.0 release in 2008. It's a very modern desktop with a lot of rich and impressive features. KDE enthusiasts will find a whole lot to like in 4.4, and users who were put off by the instability and missing functionality of previous releases might want to give it another look. For more details and some demo videos, check out the official release announcement.