I realize that this is 4+ years later but in case someone else runs
across this issue, I figured it by combining sonya1's "another solution"
with some javascript I have for ghost text to come up with this that
works for me:if (this.isNull) {app.alert("This is a required
field!");xfa.host.setFocus(this);}ENSURE THAT LANGUAGE IS SET TO
JAVASCRIPT AND NOT FORMCALC!