The JXTaskPane component is part of the SwingX (https://swingx.dev.java.net) project and is mainly a collapsible container for other components. Multiple taskpanes can be added to a JXTaskPaneContainer. This is not a must.

SyntheticaAddons provides the TaskPane-UI for every available Synthetica Look and Feel. The UI configuration can be made via UI-defaults and is part of the synth.xml file which belongs to every Synthetica Look and Feel V2.0 or above.