When you're writing an editor, a common feature is to intercept the user's typing and automatically edit the text, to make writing easier. For example, if we're typing in a list, we might want to automatically insert another bullet point when the user presses enter...

I'm writing a Mac App which includes an NSTextView. One of the things I found difficult to discover online is how to respond to when the user presses shift-tab while editing in the text view - I wanted to intercept this event to de-indent a list item...