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
String statusMessage = message;
		if (statusMessage == null) {
			statusMessage = NLS
					.bind(
							UndoMessages.AbstractWorkspaceOperation_GenericWarningMessage,
							getLabel());
		}
		return new Status(IStatus.WARNING, IDEWorkbenchPlugin.IDE_WORKBENCH,
				code, statusMessage, null);
	}
	/**
	 * Return whether the resources known by this operation currently exist.
	 * 
	 * @return <code>true</code> if there are existing resources and
	 *         <code>false</code> if there are no known resources or any one
	 *         of them does not exist
	 */
	protected boolean resourcesExist() {
		if (resources == null || resources.length == 0) {
			return false;
		}
		for (int i = 0; i < resources.length; i++) {
			if (!resources[i].exists()) {
				return false;
			}
		}
		return true;
	}
}