While playing around with the Swing 1.0.2 components, I found an additional problem that you may be interested in. As I said in my original bug report, I'm using a JTabbedPane in a BeanBox Customizer (see: 4139683). When I go to view the ToolTips available from JTabbedPane, I get the following exception:

Exception occurred during event dispatching:
java.lang.NullPointerException
        at com.sun.java.swing.ToolTipManager$JPanelPopup.show(Compiled Code)
        at com.sun.java.swing.ToolTipManager.showTipWindow(Compiled Code)
        at com.sun.java.swing.ToolTipManager.mouseMoved(Compiled Code)
        at java.awt.Component.processMouseMotionEvent(Compiled Code)
        at com.sun.java.swing.JComponent.processMouseMotionEvent(Compiled Code)
        at java.awt.Component.processEvent(Compiled Code)
        at java.awt.Container.processEvent(Compiled Code)
        at java.awt.Component.dispatchEventImpl(Compiled Code)
        at java.awt.Container.dispatchEventImpl(Compiled Code)
        at java.awt.LightweightDispatcher.retargetMouseEvent(Compiled Code)
        at java.awt.LightweightDispatcher.processMouseEvent(Compiled Code)
        at java.awt.LightweightDispatcher.dispatchEvent(Compiled Code)
        at java.awt.Container.dispatchEventImpl(Compiled Code)
        at java.awt.EventDispatchThread.run(Compiled Code)

As with my original report, this never happened with Swing 1.0.1. The ToolTips worked just fine there.