That comes close, but still doesn’t work quite right.
OnSelectChange: Set variable1 empty IF variable1 is empty
OnSelectChange: Set text box variable1 if variable1 is NOT empty
What happens here is that if I enter data in the entry field, then delete using backspace, it retains the first character I typed. It’s as if it’s not seeing that last backspace keystroke.
Here’s an attachment with an editable entry field and both a read-only entry field and text block that get updated on SelectChange of the editable field.