It does not seem possible to have a JComponent exist in a heavy-weight frame
and support tooltips. I am getting the following exception:

Exception occurred during event dispatching:
java.lang.NullPointerException
        at com.sun.java.swing.ToolTipManager$JPanelPopup.show(ToolTipManager.java:449)
        at com.sun.java.swing.ToolTipManager.showTipWindow(ToolTipManager.java:169)
        at com.sun.java.swing.ToolTipManager.mouseMoved(ToolTipManager.java:339)
        at java.awt.AWTEventMulticaster.mouseMoved(AWTEventMulticaster.java:276)
        at java.awt.Component.processMouseMotionEvent(Component.java:2329)
        at com.sun.java.swing.JComponent.processMouseMotionEvent(JComponent.java:1544)
        at java.awt.Component.processEvent(Component.java:2138)
        at java.awt.Container.processEvent(Container.java:894)
        at java.awt.Component.dispatchEventImpl(Component.java:1769)
        at java.awt.Container.dispatchEventImpl(Container.java:939)
        at java.awt.Component.dispatchEvent(Component.java:1709)
        at java.awt.LightweightDispatcher.retargetMouseEvent(Container.java:1553)
        at java.awt.LightweightDispatcher.processMouseEvent(Container.java:1482)
        at java.awt.LightweightDispatcher.dispatchEvent(Container.java:1392)
        at java.awt.Container.dispatchEventImpl(Container.java:926)
        at java.awt.Component.dispatchEvent(Component.java:1709)
        at java.awt.EventDispatchThread.run(EventDispatchThread.java:63)


This is assuming that a rootpane exists when it doesn't. This worked in swing
1.0.1, although I don't know why...the source looks like it made the same
assumption to me.