Thanks for the help.
Everything works well except there is still one issue that needs to be resolved. The <On Change> action is in an input element in a table row. However, if the user moves the cursor to a different row and not to a different element on the same row (or to a button) the action associates itself to the next row where the cursor is placed and therefore the validation message becomes relevant to that row instead of the original row where the input should have been validated. Any way to get around this?