Thank you for the feedback and the suggestion. Which code are you referring to exactly? When I open https://farm.pcibex.net/r/SsqEZD/ and enter “AP” in the “age” textbox and try to click the button (regardless of whether I filled the other fields correctly) I get an error message, which disappears as soon as I start typing again in the textbox. If I click on the button again after typing a 2-digit number in the textbox (and with the other fields correctly filled) then the experiment proceeds.
Did you include a Key element with
callback as suggest in this message to have the error message automatically disappear upon keypress?