950XL Keyboard, what is this mystery button?

[FredW]

950XL Keyboard

Probably a silly question but what is the little button between the Z and X letters for.
When pressed I get four arrows appear.
Haven't been able to find out why. Help would be much appreciated. Thanks.

 

[Jeffrey Fox]

re:

That allows you to scroll through text one letter at a time. Nice if you need to correct spelling.