A very common use case we overlooked is picking colors using the stylus. While we can assign keyboard modifiers and shortcuts to the tablet buttons, the stylus buttons have a more focused set of action, but this one is kind of missing. 

As we don't have the action API, this is usually done using modifiers (Ctrl in particular). Just adding Ctrl,Shift and Alt to the list is making the dropdown considerably less usable, so this will need design work.