When i click on a Application or Toolkit Modal dialog with the parent, i am getting NullPointer Exception in jdk7 b55 pit build. It works fine in jdk7 b51 promoted build.

Step to reproduce :-
----------------------
1) Run the attached program.
java -jar ToplevelFactory.jar
2) Select Dialog , Owner is visible, Modality type is either Applicatin_Modal or Toolkit modal. & click on "Show toplevel" button.
3) Click on the dialog, Observe that exception is thrown on console. If you see the same then the bug is reproduced.


bash-3.00# /net/sqindia.india/export/disk05/awt/karen/pit7b55/solaris-sparc/bin/java -jar ToplevelFactory.jar
Exception in thread "AWT-EventQueue-0" java.lang.NullPointerException
        at sun.awt.X11.XWindowPeer.restoreTransientFor(XWindowPeer.java:1666)
        at sun.awt.X11.XWindowPeer.removeFromTransientFors(XWindowPeer.java:1732)
        at sun.awt.X11.XWindowPeer.setModalBlocked(XWindowPeer.java:1454)
        at sun.awt.X11.XWindowPeer.setModalBlocked(XWindowPeer.java:1428)
        at java.awt.Window.setModalBlocked(Window.java:1411)
        at java.awt.Dialog.unblockWindow(Dialog.java:1597)
        at java.awt.Dialog.modalHide(Dialog.java:1483)
        at java.awt.Dialog.hideAndDisposePreHandler(Dialog.java:1215)
        at java.awt.Dialog.hide(Dialog.java:1255)
        at java.awt.Window$1DisposeAction.run(Window.java:1097)
        at java.awt.Window.doDispose(Window.java:1111)
        at java.awt.Dialog.doDispose(Dialog.java:1273)
        at java.awt.Window.dispose(Window.java:1058)
        at toplevelfactory.ControlFrame.showToplevelButtonActionPerformed(ControlFrame.java:518)
        at toplevelfactory.ControlFrame.access$500(ControlFrame.java:41)
        at toplevelfactory.ControlFrame$14.mousePressed(ControlFrame.java:618)
        at java.awt.AWTEventMulticaster.mousePressed(AWTEventMulticaster.java:280)
        at java.awt.Component.processMouseEvent(Component.java:6257)
        at javax.swing.JComponent.processMouseEvent(JComponent.java:3309)
        at java.awt.Component.processEvent(Componena:4258)
        at java.awt.Container.dispatchEventImpl(Container.java:2127)
        at java.awt.Window.dispatchEventImpl(Window.java:2609)
        at java.awt.Component.dispatchEvent(Component.java:4446)
        at java.awt.EventQueue.dispatchEvent(EventQueue.java:605)
        at java.awt.EventDispatchThread.pumpOneEventForFilters(EventDispatchThread.java:286)
        at java.awt.EventDispatchThread.pumpEventsForFilter(EventDispatchThread.java:201)
        at java.awt.EventDispatchThread.pumpEventsForFilter(EventDispatchThread.java:195)
        at java.awt.Dialog$1.run(Dialog.java:1072)
        at java.awt.Dialog$3.run(Dialog.java:1126)
        at java.security.AccessController.doPrivileged(Native Method)
        at java.awt.Dialog.show(Dialog.java:1124)
        at java.awt.Component.show(Component.java:1525)
        at java.awt.Component.setVisible(Component.java:1477)
        at java.awt.Window.setVisible(Window.java:925)
        at java.awt.Dialog.setVisible(Dialog.java:1011)
        at toplevelfactory.CoultButtonModel.setPressed(DefaultButtonModel.java:259)
        at javax.swing.plaf.basic.BasicButtonListener.mouseReleased(BasicButtonListener.java:253)
        at java.awt.Component.processMouseEvent(Component.java:6260)
        at javax.swing.JComponent.processMouseEvent(JComponent.java:3309)
        at java.awt.Component.processEvent(Component.java:6025)
        at java.awt.Container.processEvent(Container.java:2083)
        at java.awt.Component.dispatchEventImpl(Component.java:4620)
        at java.awt.Container.dispatchEventImpl(Container.java:2141)
        at java.awt.Component.dispatchEvent(Component.java:4446)
        at java.awt.LightweightDispatcher.retargetMouseEvent(Container.java:4665)
        at java.awt.LightweightDispatcher.processMouseEvent(Container.java:4328)
        at java.awt.LightweightDispatcher.dispatchEvent(Container.java:4258)
        at java.awt.Container.dispatchEventImpl(Container.java:2127)
        at java.awt.Window.dispatchEventImpl(Window.java:2609)
        at java.awt.Compos(EventDispatchThread.java:178)
        at java.awt.EventDispatchThread.run(EventDispatchThread.java:139)