if (previousUndoManager != null) {
IDocument newDocument= getDocumentProvider().getDocument(movedElement);
if (newDocument != null) {
IDocumentUndoManager newUndoManager= DocumentUndoManagerRegistry.getDocumentUndoManager(newDocument);
if (newUndoManager != null)
newUndoManager.transferUndoHistory(previousUndoManager);
}
previousUndoManager.disconnect(this);
}
if (wasDirty && changed != null) {