I actually created this issue. I wasn’t getting an error indicator (I guess that functionaliy doesn’t work as explained in the Book of Vaadin for 7.x because I never see a red !). So I created:
Anyway, I added a focuslistener to the textfield to remove the required-field-not-set style from the text field so when the user clicks to enter the missing information the error icon disappears.
It would be nice if the functionality worked as described in the Book of Vaadin 7 but this is a suitable workaround.