Bug 77649 'Refactor -> Undo' enabled after consecutive change
I200411022000 Having: package test2; public class A { public C c= new C(); public void foo() { } } package test2; public class B { public void bar() { new A().foo(); } } package test2; public class C { } and: - open all 3 CUs - move A#foo() to C - remove 'a' from 'new A().c.foo(a);' in B - save B - Refactor -> Undo -> lost parenthesis in B because undo did no longer match
org.eclipse.ltk.core.refactoring/src/org/eclipse/ltk/core/refactoring/IUndoManager.java
* @return the top most undo name. Returns <code>null</code> if there 
	 * aren't any changes to undo.
	 */
	public String peekUndoName();
	
	/**
	 * Undo the top most undo change.
	 * 
	 * @param query a proceed query to decide how to proceed if the validation
	 *  checking of the undo change to perform returns a non OK status and the
	 *  status isn't a fatal error. If <code>null</code> is passed in the the 
	 *  undo proceeds if the status is not a fatal error.
	 * @param pm a progress monitor to report progress during performing
	 *  the undo change
	 * 
	 * @throws CoreException if performing the undo caused an exception
	 */	
	public void performUndo(IValidationCheckResultQuery query, IProgressMonitor pm) throws CoreException;
	/**
	 * Returns <code>true</code> if there is anything to redo, otherwise
	 * <code>false</code>.
	 * 
	 * @return <code>true</code> if there is anything to redo, otherwise
	 *  <code>false</code>
	 */
	public boolean anythingToRedo();
	
	/**
	 * Returns the name of the top most redo.
	 *