You need three event handlers:
1) onChanging event on the left edittext.
2) onChanging event on the right one.
1) the checkbox needs a click event which changes the event handlers
for the the two edittext areas. If it's checked, it needs to make the
onChanging event reflect the text in the other (textedit2.text =
texteidt1.text), and when unchecked, to remove that functionality.
thank you very much.