There are many different places in Mangia! where you will either need to or have the option of providing a Term (whether a Category, an ingredient, or whatever). These places (text boxes) have a consistent clue to their nature: wherever one of these text boxes occurs you will see a Dictionary Button (in the form of a hand opening a dictionary) nearby. Clicking on the Dictionary Button and selecting from the resulting pop-up menu inserts a Term into the box. Of course, you can also type the Term into the box. But there is a third alternative: after you type the first few characters, the Dictionary Button may be marked with an ellipsis (...). If so, hitting Command-? will fill in the rest of the Term for you.
There are two cases in which Mangia! can’t complete the Term for you. You might have typed characters that aren’t part of any Term; naturally then it won’t know how to complete it. Second, if the letters you have typed begin more than one Term (as “pe” begins both “pepper” and “pecan”), then Mangia! can’t know which you mean. However, it will add any letters it can.
You can also type a few characters, then select them with the mouse. Then, if you click on the Dictionary Button, the menu will show you Terms that include those characters anywhere in their names. For example, typing and selecting “sal” might result in a choice between “salt,” “salmon,” “marsala,” etc.
