Iconbox works just as expected when I set it to the exact panel where I want it to stay. If by any reason I have to move it to another panel, as soon as the movement is completed, it will render useless the icons it already had and create new icons, as duplicates of the old ones. One critical part of this bug is that if I right-click on any of the "dead" icons (the ones that were there before the movement) the whole panel dies with a segmentation fault.
Thanks for the report. It looks like the problem was easier to fix than I thought. With SVN revision 23889 I can safely move the iconbox from one panel to another. If I had known it would be this easy, I would not have asked you to report it (although is does look nice if you can add a bug number to the commit message ;-). Please reopen if it doesn't work for you. Thanks again.