Before revision: Such situations may arise from the following: precision requirements (e.g., technical drawing) disabled user or ergonomics issues environmental limits (e.g., vibration in car or plane) broken/missing/unavailable equipment In 1987, Macintosh Operating System 4.2 Easy AccessSystem 4, 1987 introductions: System 4.2 , provided MouseKeys support to all applications.
After revision: Such situations may arise from the following: precision requirements (e.g., technical drawing) disabled user or ergonomics issues environmental limits (e.g., vibration in car or plane) broken/missing/unavailable equipment In 1987, Macintosh Operating System 4.2 Easy Access , provided MouseKeys support to all applications.