I love docking. Three years ago when I wrote a docking system there was next to nothing. Now we have docking implementations coming out of the wood work at the rate of about one every three months. FlexDock is still the only completely open source option I know of. Today we have another dual licensed option to compete with InfoNode. It looks very polished from my brief glance.
VLSolutions Docking Framework VLSolutions has developped a true multiplatform docking framework, tested and optimized for Windows 98 to XP, Mac OS X (10.3) and Linux KDE/Gnome, with java runtime 1.4 and 1.5 (where available). The VLDocking Framework 1.0 is distributed with dual licensing : open source (GPL compatible) and commercial. Notable features are :
* Abstract DockingContainers provided with default implementations : simple docking/ tabbed docking / auto-hide expandable buttons
* Well documented API and tutorial
* Look and Feel friendly
* Java Web Start Demo is a true application (an online forum)
* Affordable commercial license
* Sources & build system freely downloadable