This dialog box allows you to change the font used in the editing window and/or used in the various dialog boxes.
There are three types of fonts which can be set:
Editing Area:        Used for the edit window. This is a normally a fixed width font.
Dialog boxes:       Used for dialog box buttons, menus and prompt fields.
Tables & trees:    Used for displaying information in a dialog box. Using a smaller font can allow you to see more entries in the dialog, e.g. files or functions.