CardKB ESC from CORE2

[gcem5stack]

Hi,
As you know, we can get string or key from the keyboard to write something on a screen (as UIFLOW sample: https://docs.m5stack.com/en/unit/cardkb).
And to clear the string on a screen you press Esc on a keyboard....
But how to clear the string value from the ESP and UIflow, like a reset() without pass through the keyboard physicaly???? getString made the sum of string(s)....
getKey => return 1 key
getString => return all the characters (It is a normal behaviour???)

a helping hand would be much appreciated.
Thx by advance,