i got peculiar requiremet regarding to jgoundomanager.
I had an editor which is the combination of JGODocument and two panels.
The two panels namely left panel and right panel. These panels contains JTree. In the middle i had JGoDocument. I can drag and drop some object on to jgodocument and then link this component with the nodes of left tree and Right tree. Now i have to implement the UndoManager for this editor. So now my problem is how to register the left tree and right tree panels with undomanager.

JGoUndoManager is a subclass of javax.swing.undo.UndoManager (and JGoDocumentChangedEdit extends AbstractUndoableEdit), so I believe you should be able to use the standard undo/redo implementation techniques that Swing recommends.
You just need to use a single JGoUndoManager, and make sure each of your UndoableEdits either gets added to the JGoUndoManager.getCurrentEditVector if part of an ongoing transaction, just like what JGoUndoManager.documentChanged does, or else gets added as a separate top-level edit to the undo manager.

How can we register a JPanel to swing undomanager ? Can i get a sample code on this?

I don’t think we have any examples of this, but there ought to be a Sun tutorial about UndoManager, and you should be able to find books and other information about the Swing undo mechanism.