Bug 88352 Operation supports leaks contexts via action handler
I20050315-1100 Susan, this is a different leak from the one that I reported. Test Case: 1. open text editor 2. close text editor ==> DefaultUndoManager is leaked due to undo/redo actions handlers still holding on to the context.
bundles/org.eclipse.core.commands/src/org/eclipse/core/commands/operations/IUndoableOperation.java
* <p>
 * Note: This class/interface is part of a new API under development. It has
 * been added to builds so that clients can start using the new features.
 * However, it may change significantly before reaching stability. It is being
 * made available at this early stage to solicit feedback with the understanding
 * that any code that uses this API may be broken as the API evolves.
 * </p>
 * 
 * @since 3.1
 * @experimental
 */
public interface IUndoableOperation {
	/**
	 * Add the specified context to the operation. If the context is already
	 * present, do not add it again.
	 * 
	 * @param context -
	 *            the context to be added
	 */
	void addContext(IUndoContext context);
	/**
	 * <p>
	 * Returns whether the operation can be executed in its current state.
	 * 
	 * <p>
	 * Note: This method may be used to enable UI commands, so the computation
	 * must be fast. If necessary, this method can be optimistic in its
	 * computation and return an error status during actual execution if it is
	 * determined later that the operation cannot actually execute.
	 *