Gui: don't make QuantitySpinBox dependent on implementation details of its base class

src/Gui/QuantitySpinBox.cpp

@@ -337,8 +337,11 @@ QuantitySpinBox::~QuantitySpinBox()
 
 void QuantitySpinBox::bind(const App::ObjectIdentifier &_path)
 {
-    ExpressionBinding::bind(_path);
+    ExpressionSpinBox::bind(_path);
+}
 
+void QuantitySpinBox::showIcon()
+{
     iconLabel->show();
 }
 

src/Gui/QuantitySpinBox.h

@@ -145,6 +145,7 @@ protected Q_SLOTS:
 protected:
     void setExpression(std::shared_ptr<App::Expression> expr) override;
     void openFormulaDialog() override;
+    void showIcon() override;
     StepEnabled stepEnabled() const override;
     void showEvent(QShowEvent * event) override;
     void hideEvent(QHideEvent * event) override;

src/Gui/SpinBox.cpp

@@ -65,6 +65,11 @@ void ExpressionSpinBox::bind(const App::ObjectIdentifier &_path)
 {
     ExpressionBinding::bind(_path);
 
+    showIcon();
+}
+
+void ExpressionSpinBox::showIcon()
+{
     int frameWidth = spinbox->style()->pixelMetric(QStyle::PM_SpinBoxFrameWidth);
     lineedit->setStyleSheet(QString::fromLatin1("QLineEdit { padding-right: %1px } ").arg(iconLabel->sizeHint().width() + frameWidth + 1));
 

src/Gui/SpinBox.h

@@ -60,6 +60,7 @@ protected:
 
     void onChange() override;
     virtual void setNumberExpression(App::NumberExpression*) = 0;
+    virtual void showIcon();
     void resizeWidget();
 
     bool handleKeyEvent(const QString&);