Whenever you search for combinations of words (combined with AND, OR or NOT) then FindWord immediately eliminates all choices which do not lead to any document - so you always get at least one resulting file.
To exemplify this we'll take a delivery service specialised in soups. All the soups contain water, salt, potatoes, herbs and butter. Their further contents differ as follows:
FindWord initially displays the four ingredients leeks, paprikas, tomatoes and onions. If the user clicks on "onions" she'll see that they are contained in two types of soup:
To refine her search, she clicks on the "AND"-Operator. The words leek and paprika disappear immediately, because no soup containing onions contains either of these ingredients.
She now selects "Tomatoe" and sees straight away that only "Soup 3" contains both onions and tomatoes. Her search is finished and she can order her soup!
Optionally you can view the chronological growth of a query in an extra floating window, which is very useful for more complicated researches: