Gui: fix locale number formatting propagation

src/Gui/QuantitySpinBox.cpp

@@ -139,7 +139,7 @@ public:
     {
         try {
             QString copy = str;
-            copy.remove(QLocale().groupSeparator());
+            copy.remove(locale.groupSeparator());
 
             result = Base::Quantity::parse(copy);
             value = result.getValue();
@@ -162,8 +162,6 @@ public:
         const bool plus = max >= 0;
         const bool minus = min <= 0;
 
-        auto locale = QLocale();
-
         switch (len) {
         case 0:
             state = max != min ? QValidator::Intermediate : QValidator::Invalid;
@@ -292,6 +290,7 @@ end:
         return res;
     }
 
+    QLocale locale;
     bool validInput;
     bool pendingEmit;
     QString validStr;
@@ -314,6 +313,7 @@ QuantitySpinBox::QuantitySpinBox(QWidget *parent)
       ExpressionSpinBox(this),
       d_ptr(new QuantitySpinBoxPrivate(this))
 {
+    d_ptr->locale = locale();
     this->setContextMenuPolicy(Qt::DefaultContextMenu);
     QObject::connect(lineEdit(), SIGNAL(textChanged(QString)),
                      this, SLOT(userInput(QString)));