Maybe the definition of the word has changed.
A WIDOW is the last line of a paragraph that has found itself all alone at the top of the following page.
It is NOT a single word at the end of a paragraph on a line by itself.
Yet it continually amazes me that art directors, professional designers, and professors who teach graphic design do not know this. I encounter daily young designers who will take great pains to ensure words like "combustible" and "nationality" are not without company.
Of course, lone words less than four letters -- please don't call them widows, as they are not -- should find their way back among their friends, if possible. Otherwise, stop spending precious time trying to solve something that is neither an error or a problem. And when I ask you, "where's my ad?" don't whine and look pleadingly toward Heaven (or the pigeons mating in the rafters) and mumble, "just fixing a few widows; it will only be a minute." There are no widows in a one-page ad!
There. I've said it.