Before revision: It serializes keystrokes instead of pressing multiple keys at a time, allowing the user to press and release a modifier key, such as , , , or the , and have it remain active until any other key is pressed.
After revision: It serializes keystrokes instead of pressing multiple keys at a time, the user is allowed; to press and release a modifier key, such as , , , or the , and have it remain active until any other key is pressed.