Bait and switch - an only enter text into their box in free version

My right arm is in a sling so this looked promissing.

But the free version can only type into their little box, then youd have to copy and paste. But frustrating that this is not clearly disclosed in their description.

Also, I have remapped caps-lock to be a second Cmd key, so not able to turn it on.

87830 about One-Hand Keyboard: Free One-Hand Typing