When you type punctuation, Aurora knows to back up over the extra space, type the punctuation, and then add the right number of additional spaces afterwards. When you start your next sentence, it will also capitalize the first word for you. This helps slow typists reduce keystrokes, and makes sure that people who have problems with punctuation get the right number of spaces afterwards and remember to capitalize the first word of a sentence. If you don't need this type of help, you can turn it off.