Several menu items are described in this help text as being "undoable". You may find that the Undo item in the Edit menu is not always enabled when you expect it to be. One cause of this situation is that undoable operations are "committed" (so they are no longer undoable) when you save the subscription file, do a tune-up, or export a .newsrc file. If you have a preference set to automatically save your subscription file, seeming unrelated operations will be committed when you are not expecting it.
