Hi Michael, I have made the change. Please try again.
Florian
After the java 1.6.0_51 update, workbench is no longer working on osx.It starts up, but the frames remain empty.Possibly UIManager.setLookAndFeel() should be called in a swing thread(with SwingUtilities) see http://stackoverflow.com/questions/17204465/how-does-java-for-os-x-2013-004-affect-break-swing-applications/17226346#17226346 Michael
