feature allows you to
successively select expanding blocks of code so that you can easily
select any expression in the code by placing the caret somewhere
inside it and pressing
a few times.
ReSharper | Edit | Extend Selection
Shrink Selection does exactly the opposite. Press Ctrl+Shift+W or choose ReSharper | Edit | Shrink Selection .
For guidelines on how to configure this feature to take CamelCase into account, see CamelHumps.