OK !
Text input are very inspiring, I have still few ideas left (but I dont want to spam you with all of them :P)
Though, I think something which could be useful right from the start is the ability to have an horizontal bar when a line is too long (just like you have done with the vertical one).
Also for the moment, it doesn't scroll if click drag select a line longer than the view (nor to the left, nor the right). The only way to get back to the begining is to enter a new line, or click on a shorter line.