KDE (meaning both the window manager KWin and the whole desktop) in version 3.2 has been updated to support the latest version of the EWMH (a.k.a. NETWM) window manager specification (including most things from the draft version 1.3). This, besides other things like better handling of fullscreen windows, means that it should be easy to replace KDE's default window manager KWin with other compliant window managers.
In practice there may be some problems, caused by bugs in KDE, bugs in other window managers, different interpretations of some parts of the specification or KDE extensions to the specification that haven't been standardized. Also other window managers are unlikely to obey KDE settings about number of virtual desktops, their names, colors, and similar.
This page tries to collect these problems, and offer solutions for them. I'd be interested in feedback from you about which window managers really work with KDE 3.2 and what are the possible problems with them.
NOTE: Please don't send me bugreports about other window managers, especially if they have poor or non-existant support for the window manager specification. Report the problems to the developers of those window managers. If a problem is caused by KDE (a bug in the implementation, incorrect interpretation of the specification,...), please report them to KDE bugs database for product 'kwin' (component 'compatibility').
In order to start KDE with other window manager, the shell variable KDEWM must contain the name (executable name without the path) of the window manager. E.g. in order to run KDE with OpenBox, put 'export KDEWM=openbox' in your ~/.profile (or equivalent) file. If KDEWM is empty, KWin will be started.
In order to temporarily switch to a different window manager, many window managers support a command line option that will make it replace the currently running window manager (manually killing the current window manager is dangerous, as that can lead to lost focus and desktop becoming unusable). The option is usually '--replace' or '-replace', so e.g. Alt+F2 'openbox --replace' replaces KWin with OpenBox and Alt+F2 'kwin --replace' starts KWin again. Ffor this to work, both window managers must implement the window manager selection handling as described in the ICCCM.
Window managers must have a decent support for the window manager specification in order to be usable with KDE. The specification main page has a list window managers that have some level of support for it, it's possible there exist more window managers that aren't listed there.
(Briefly tested) Version 3.1 of OpenBox seems to work quite fine. KDE tray proxy (see below) doesn't work reliably with it (most probably OpenBox bug).
(Briefly tested) Recent versions of Metacity seem to work mostly fine. Clicking taskbar entries causes the respective window to be moved to the current desktop instead of switching to its desktop (it's possible this problem can show also in other cases). A Metacity bugreport about this issue has been opened (#128380).
(From Troy Unrau <troy tblog ath cx>) Enlightenment-0.16.5 works fine with a few errors. Kdesktop doesn't work quite as expected. In E's settings, there is an option to 'enable KDE support' which once enabled, properly puts kdesktop into the root window and such - but only on one of the virtual desktops... The other virtual desktops are all still using the E backgrounds and have no desktop icons. No apps show up in the taskbar at all, regardless of how they are started -- however, they show up just fine in E's built in task manager. So basically, if one is using kicker, just removing the taskbar and using E's is fine.
If you submit information about other window managers, it will be added here.
In order to make KDE systray icons work with window managers that don't have support for the KDE tray protocol, the kdetrayproxy kded module must be installed. This module is auto-loaded, so there's no need to start it manually after installation.
Note that kdetrayproxy is included with KDE starting with KDE3.3.0.
Source
RPM package for SUSE 9.0
The standalone menubar uses KDE extension to the specification, and it's unlikely any other window manager supports it at the present time. It is possible that with some window managers it will work when swallowed by the Kicker Menu applet.
Lubos Lunak <l.lunak suse.cz> <l.lunak kde.org>