diff --git a/src/frontends/qt4/Validator.cpp b/src/frontends/qt4/Validator.cpp
index f39e503ae5..f376afbe2a 100644
--- a/src/frontends/qt4/Validator.cpp
+++ b/src/frontends/qt4/Validator.cpp
@@ -92,8 +92,7 @@ LengthAutoValidator::LengthAutoValidator(QWidget * parent)
 
 QValidator::State LengthAutoValidator::validate(QString & qtext, int & dummy) const
 {
-	string const text = fromqstr(qtext);
-	if (text == "auto")
+	if (qtext == "auto")
 		return QValidator::Acceptable;
 	return LengthValidator::validate(qtext, dummy);
 }