I've already experienced this problem in several of my worlds. I'm creating an article and I want to sort it under a category or a parent article and later I realize that I also want it under a second article or category. I especially see this with character articles, for example, I want to sort a female character under the category of her birth family, as well as a category of the family she marries into, because this helps me keep better track of my characters.   I would like to propose that an article can be sorted under multiple categories and/or parent articles. Ideally, you would be able to sort it under both one or more categories as well as one or more parent articles, but if that is not possible, I would be more than happy to be able to add an article to multiple categories or multiple parent articles.