I have a couple suggestion regarding the validation error messages:
1) When enabling validation on a per question basis, I've noticed that the default error message for a multiple choice question which requires only one response is "please choose at least one answer." I think this is confusing for respondents as in a case like this, we only want them to choose a single answer, not more than one.
2) I have a few questions in my survey that are followed by open-ended text comment boxes. QuestionPro counts each one of these comment boxes as a question (even though I don't) so that any validation error messages that pop up on questions that follow do not reference the correct question number. Very confusing for any respondent who uses the validation error hyperlinks at the top of the page to access the questions for which they're missing responses.

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