introduce constant for editor tpye

GUI/Models/ItemWithMaterial.cpp

@@ -51,5 +51,5 @@ ItemWithMaterial::ItemWithMaterial(const QString& model_type) : SessionGraphicsI
 {
     addProperty(P_MATERIAL, GUI::Model::MaterialItemUtils::defaultMaterialProperty().variant())
         ->setToolTip("Material this item is made of")
-        .setEditorType("ExtMaterialEditor");
+        .setEditorType(ExternalPropertyEditor::EDITOR_TYPE);
 }

GUI/Views/PropertyEditor/CustomEditors.cpp

@@ -35,6 +35,8 @@
 #include <QToolButton>
 #include <cmath>
 
+const QString ExternalPropertyEditor::EDITOR_TYPE = "MaterialEditor";
+
 namespace {
 //! Single step for QDoubleSpinBox.
 

GUI/Views/PropertyEditor/CustomEditors.h

@@ -15,6 +15,7 @@
 #ifndef BORNAGAIN_GUI_VIEWS_PROPERTYEDITOR_CUSTOMEDITORS_H
 #define BORNAGAIN_GUI_VIEWS_PROPERTYEDITOR_CUSTOMEDITORS_H
 
+#include "WinDllMacros.h"
 #include <QVariant>
 #include <QWidget>
 
@@ -47,11 +48,13 @@ protected:
 
 //! Editor for ExternalProperty variant.
 
-class ExternalPropertyEditor : public CustomEditor {
+class BA_CORE_API_ ExternalPropertyEditor : public CustomEditor {
     Q_OBJECT
 public:
     explicit ExternalPropertyEditor(QWidget* parent = nullptr);
 
+    static const QString EDITOR_TYPE;
+
 private slots:
     void buttonClicked();