Create text on second Part(volume) of object

src/libslic3r/TextConfiguration.hpp

@@ -103,6 +103,15 @@ struct FontItem
         wx_mac_font_descr // path is font descriptor generated by wxWidgets on windows
     };
 
+    bool operator==(const FontItem &other) const {
+        return 
+            type == other.type &&
+            prop == other.prop &&
+            name == other.name &&
+            path == other.path
+            ;
+    }
+
     // undo / redo stack recovery
     template<class Archive> void serialize(Archive &ar)
     {