diff --git a/src/plugins/qmldesigner/designercore/model/propertyparser.cpp b/src/plugins/qmldesigner/designercore/model/propertyparser.cpp
index 46f2e111914..514c1ff68c6 100644
--- a/src/plugins/qmldesigner/designercore/model/propertyparser.cpp
+++ b/src/plugins/qmldesigner/designercore/model/propertyparser.cpp
@@ -87,8 +87,8 @@ QPointF pointFFromString(const QString &s, bool *ok)
 
     bool xGood, yGood;
     int index = s.indexOf(QLatin1Char(','));
-    qreal xCoord = s.left(index).toDouble(&xGood);
-    qreal yCoord = s.mid(index+1).toDouble(&yGood);
+    qreal xCoord = s.leftRef(index).toDouble(&xGood);
+    qreal yCoord = s.midRef(index+1).toDouble(&yGood);
     if (!xGood || !yGood) {
         if (ok)
             *ok = false;
@@ -110,12 +110,12 @@ QRectF rectFFromString(const QString &s, bool *ok)
 
     bool xGood, yGood, wGood, hGood;
     int index = s.indexOf(QLatin1Char(','));
-    qreal x = s.left(index).toDouble(&xGood);
+    qreal x = s.leftRef(index).toDouble(&xGood);
     int index2 = s.indexOf(QLatin1Char(','), index+1);
-    qreal y = s.mid(index+1, index2-index-1).toDouble(&yGood);
+    qreal y = s.midRef(index+1, index2-index-1).toDouble(&yGood);
     index = s.indexOf(QLatin1Char('x'), index2+1);
-    qreal width = s.mid(index2+1, index-index2-1).toDouble(&wGood);
-    qreal height = s.mid(index+1).toDouble(&hGood);
+    qreal width = s.midRef(index2+1, index-index2-1).toDouble(&wGood);
+    qreal height = s.midRef(index+1).toDouble(&hGood);
     if (!xGood || !yGood || !wGood || !hGood) {
         if (ok)
             *ok = false;
@@ -137,8 +137,8 @@ QSizeF sizeFFromString(const QString &s, bool *ok)
 
     bool wGood, hGood;
     int index = s.indexOf(QLatin1Char('x'));
-    qreal width = s.left(index).toDouble(&wGood);
-    qreal height = s.mid(index+1).toDouble(&hGood);
+    qreal width = s.leftRef(index).toDouble(&wGood);
+    qreal height = s.midRef(index+1).toDouble(&hGood);
     if (!wGood || !hGood) {
         if (ok)
             *ok = false;
@@ -161,9 +161,9 @@ QVector3D vector3DFromString(const QString &s, bool *ok)
     bool xGood, yGood, zGood;
     int index = s.indexOf(QLatin1Char(','));
     int index2 = s.indexOf(QLatin1Char(','), index+1);
-    qreal xCoord = s.left(index).toDouble(&xGood);
-    qreal yCoord = s.mid(index+1, index2-index-1).toDouble(&yGood);
-    qreal zCoord = s.mid(index2+1).toDouble(&zGood);
+    qreal xCoord = s.leftRef(index).toDouble(&xGood);
+    qreal yCoord = s.midRef(index+1, index2-index-1).toDouble(&yGood);
+    qreal zCoord = s.midRef(index2+1).toDouble(&zGood);
     if (!xGood || !yGood || !zGood) {
         if (ok)
             *ok = false;