When editing the column properties from inside a form, if changing either the column label or the question type, any help text that the user has entered get deleted. While you can always edit the header in the sheet itself, it does not make much sense for longer forms that may have taken multiple drafts (questions deleted/moved around = extra columns/columns out of order). It would also be useful if questions that are deleted, result in a deletion of their corresponding column to mitigate sheet cleanup.
I agree with the help text. This is a huge pet peeve of mine when I am creating new forms and updating forms. It would be a huge time save so I don't have to toggle back and forth between the sheet to update column properties as a work around.