I just download Keytweak and use a Dvorak keyboard. I want to change only three keys 'A', 'O' and '"'. But when I tried to use Keytweak (when I tried to swap '-' and 'A' it left 'A' where it was and put '"' where the '-' is). I tried to undo it, but the changes didn't take efect. Now, if I type '-' then '"' comes up and the 'A' is still where is was. How can I overcome this?