Bug 156865 Undo / Redo marker actions not updated
I20060906-1200 If a file gets delete after adding/changing/removing a marker then the Undo and Redo actions are not updated and still show, e.g. Undo Add Task Redo Add Task Executing the undo or redo does nothing (no feedback, no .log entry) and the undo and redo menu text remains the same and enabled.
bundles/org.eclipse.ui.ide/src/org/eclipse/ui/ide/undo/AbstractWorkspaceOperation.java
*/
	public IStatus computeRedoableStatus(IProgressMonitor monitor) {
		IStatus status = Status.OK_STATUS;
		IResourceChangeDescriptionFactory factory = ResourceChangeValidator
				.getValidator().createDeltaFactory();
		if (updateResourceChangeDescriptionFactory(factory, false)) {
			boolean proceed = IDE
					.promptToConfirm(
							getShell(null),
							UndoMessages.AbstractWorkspaceOperation_SideEffectsWarningTitle,
							NLS
									.bind(
											UndoMessages.AbstractWorkspaceOperation_RedoSideEffectsWarningMessage,
											getLabel()), factory.getDelta(),
							modelProviderIds, true );
			if (!proceed) {
				status = IOperationHistory.OPERATION_INVALID_STATUS;
				markInvalid();
			}
		}
		return status;
	}
	/**
	 * Update the provided resource change description factory so it can
	 * generate a resource delta describing the result of an undo or redo.
	 * Return a boolean indicating whether any update was done. The default
	 * implementation does not update the factory. Subclasses are expected to
	 * override this method to more specifically describe their modifications to
	 * the workspace.
	 *