KWin
KWin
KWin is the windowmanager of KDE. It paints the windowdecoration, the bar on top of every window with (configurable) buttons like close, maximize and minimize. It also handles placing of windows and switching between them.
compositing
KWin supports compositing, which means using 3D effects for handling your windows. This can make windowmanagement smoother, easier, more efficient and more natural. It’s hardware requirements are very modest and pretty much every reasonably modern system since 2002 supports it. There are still some issues with certain hardware, more info about that can be found on techbase
New in KDE 4.2
Information about what's new in KDE 4.2 can be found at the following links: