Eclipse Nebula PShelf Widget for Swing
By Geertjan-Oracle on Jul 13, 2010
I found commercial versions of the above component, i.e., in its Swing version, and then found this written in 2005, but still completely valid:
Using the above, here's the result:
Nice thing is that each of the additions to the outlook panel could come from the layer, making the component pluggable, in the same way as shown in the article Pluggable JXTaskPane.