Editing Fields (HI Guide)

Inside Macintosh: Macintosh Human Interface Guidelines / Part 2 - The Interface Elements: Chapter 10 - Behaviors / Editing Text

Editing Fields

If an application isn't primarily a text application, but does use text in text entry fields (such as in a dialog box), you may not need to provide the full text-editing capabilities described so far. In Macintosh applications, the simplest way to implement text editing is to use TextEdit, or to use the Dialog Manager, which in turn uses TextEdit. It's important, however, that whatever editing capabilities the application provides under these circumstances be upward-compatible with the full text-editing capabilities. The application should support the following editing capabilities:

The user can select the whole field and type in a new value, delete text, select a substring of the field and replace it, and select a word by double-clicking.
The user can choose Undo, Cut, Copy, Paste, and Clear, as described in "The Edit Menu" beginning on page 87 in Chapter 4, "Menus."

In addition, you can support intelligent cut and paste. (TextEdit does not provide this.) Even applications with only minimal text editing should perform appropriate edit checks. For example, if the only legitimate value
for a field is a string of digits, the application should alert the user if any nondigits are typed. The alert message might remind the user that the letters
l and o can't be used in place of the numerals 1 and 0. Alternatively, the application could wait until the user is through typing before checking the validity of a field's contents. In this case, the appropriate time to check
the field is when the user clicks anywhere other than in the field or presses the Return, Enter, or Tab key.