Move make_arrow_button to element_factory interface

libs/ui/include/psemek/ui/default_element_factory.hpp

@@ -20,13 +20,7 @@ namespace psemek::ui
 		std::shared_ptr<checkbox> make_checkbox(bool value) override;
 		std::shared_ptr<slider> make_slider() override;
 		std::shared_ptr<spinbox> make_spinbox() override;
-
-		// directions:
-		// 0 - up
-		// 1 - down
-		// 2 - left
-		// 3 - right
-		std::shared_ptr<button> make_arrow_button(int direction);
+		std::shared_ptr<button> make_arrow_button(int direction) override;
 
 	private:
 		psemek_declare_pimpl

libs/ui/include/psemek/ui/element_factory.hpp

@@ -33,6 +33,12 @@ namespace psemek::ui
 		virtual std::shared_ptr<checkbox> make_checkbox(bool value);
 		virtual std::shared_ptr<slider> make_slider();
 		virtual std::shared_ptr<spinbox> make_spinbox();
+		// directions:
+		// 0 - up
+		// 1 - down
+		// 2 - left
+		// 3 - right
+		virtual std::shared_ptr<button> make_arrow_button(int direction);
 
 		virtual ~element_factory() {}
 	};

libs/ui/source/element_factory.cpp

@@ -82,4 +82,6 @@ namespace psemek::ui
 
 	std::shared_ptr<spinbox> element_factory::make_spinbox() { return nullptr; }
 
+	std::shared_ptr<button> element_factory::make_arrow_button(int) { return nullptr; }
+
 }