A fast, standards compliant, light-weight, extensible window manager for the X Window system, distributed under the terms of the GNU General Public License.
Openbox is fully functional as a stand-alone working environment, or can be used as a drop-in replacement for the default window manager in the Gnome or KDE desktop environments.
Since version 3 Openbox is not any longer based on the Blackbox codebase, but a completely new window manager. The visual appearance although is still based on Blackbox. So the menu looks like the old one, but the toolbar has been removed meanwhile. The dock is available in version 3, too, to be able using WindowMaker dockapps for example.
The configuration files have changed, too. While Openbox' version 2 was based on Blackbox code it used the same configuration file syntax. Now the configuration is written in XML. There is one file for the main configuration and one to configure the menu.
It is possible now to set up mouse actions and key bindings in the main configuration file, too, so there is no need for the keygrabber epist anymore, which has been used in version 2 as additional application.
Openbox is still theme-able, but there are not that many themes available for version 3 yet.
Here are some of the main features in Openbox3:
For more info and documentation take a look at http://icculus.org/openbox/