you can do whatever you wan with the keys you just need to give the right formula position in X to the blinking cursor ! and you can also play with x,y and scale too ( for a selection
square for example)
if you add an event every tick left key down, then you can change the formula for the blinking cursor and it works every time !
if you did a mistake in your text dont use left but just use backspace, that's what i do and it remove the wrong letter (like in the video)
for example if i type something wrong in my app i just added a function "enter" erase everything typed in text box and then you restart typing