Bug fix: 4726458 - Memory leak in sun.awt.X11.XGlobalCursorManager - backport to 6u23 from java 7

[Janda Martin]

I struggled with strong references to Frame/Dialog due to strong reference in 
  XGlobalCursorManager.nativeContainer  

bug: http://bugs.sun.com/bugdatabase/view_bug.do?bug_id=4726458

Bug is fixed in Java 7 build 17. Please can you consider backport to 6u23.

XGlobalCursorManager.nativeContainer replaced with WeakReference<Component> 
nativeContainer ...

Thank you very much.

  Martin