diff --git a/Arrangement_on_surface_2/demo/Arrangement_on_surface_2/CMakeLists.txt b/Arrangement_on_surface_2/demo/Arrangement_on_surface_2/CMakeLists.txt
index cda11985cb2..667e3752d68 100644
--- a/Arrangement_on_surface_2/demo/Arrangement_on_surface_2/CMakeLists.txt
+++ b/Arrangement_on_surface_2/demo/Arrangement_on_surface_2/CMakeLists.txt
@@ -2,6 +2,7 @@
 
 cmake_minimum_required(VERSION 3.1...3.15)
 project( Arrangement_on_surface_2_Demo )
+set(CMAKE_CXX_STANDARD 14)
 
 if(NOT POLICY CMP0070 AND POLICY CMP0053)
   # Only set CMP0053 to OLD with CMake<3.10, otherwise there is a warning.
@@ -14,78 +15,88 @@ if (NOT CMAKE_BUILD_TYPE)
       "Choose the type of build, options are: Debug Release" FORCE)
 endif()
 
+find_package(Qt5 COMPONENTS Gui Widgets)
+if (NOT Qt5_FOUND)
+  message(FATAL_ERROR "This demo requires Qt5, and will not be compiled.")
+endif()
+
 find_package(CGAL COMPONENTS Core Qt5)
 include(${CGAL_USE_FILE})
-set(CMAKE_CXX_STANDARD 14)
 
-find_package(Qt5 QUIET COMPONENTS Gui Widgets)
+if (NOT CGAL_FOUND)
+  message(FATAL_ERROR "This demo requires CGAL, and will not be compiled.")
+endif()
+
+if (NOT CGAL_Core_FOUND)
+  message(FATAL_ERROR "This demo requires CGAL_Core, and will not be compiled.")
+endif()
+
+if (NOT CGAL_Qt5_FOUND)
+  message(FATAL_ERROR "This demo requires CGAL_Qt5, and will not be compiled.")
+endif()
 
 add_definitions(-DQT_NO_KEYWORDS)
 
-if ( CGAL_FOUND AND CGAL_Qt5_FOUND AND Qt5_FOUND AND CGAL_Core_FOUND)
-  include_directories( ./ )
-  # Arrangement package includes
-  include_directories(BEFORE ../../include)
+include_directories( ./ )
+# Arrangement package includes
+include_directories(BEFORE ../../include)
 
-  qt5_wrap_ui(arrangement_2_uis
-              ArrangementDemoWindow.ui
-              NewTabDialog.ui
-              OverlayDialog.ui
-              ArrangementDemoPropertiesDialog.ui
-              AlgebraicCurveInputDialog.ui)
+qt5_wrap_ui(arrangement_2_uis
+            ArrangementDemoWindow.ui
+            NewTabDialog.ui
+            OverlayDialog.ui
+            ArrangementDemoPropertiesDialog.ui
+            AlgebraicCurveInputDialog.ui)
 
-  qt5_wrap_cpp(CGAL_Qt5_MOC_FILES
-               ArrangementDemoWindow.h
-               ArrangementDemoTab.h
-               GraphicsViewCurveInput.h
-               Callback.h
-               OverlayDialog.h
-               ArrangementDemoPropertiesDialog.h
-               AlgebraicCurveInputDialog.h
-               ColorItemEditor.h
-               DeleteCurveModeItemEditor.h
-               PropertyValueDelegate.h)
+qt5_wrap_cpp(CGAL_Qt5_MOC_FILES
+             ArrangementDemoWindow.h
+             ArrangementDemoTab.h
+             GraphicsViewCurveInput.h
+             Callback.h
+             OverlayDialog.h
+             ArrangementDemoPropertiesDialog.h
+             AlgebraicCurveInputDialog.h
+             ColorItemEditor.h
+             DeleteCurveModeItemEditor.h
+             PropertyValueDelegate.h)
 
-  qt5_add_resources(CGAL_Qt5_RESOURCE_FILES ArrangementDemoWindow.qrc)
+qt5_add_resources(CGAL_Qt5_RESOURCE_FILES ArrangementDemoWindow.qrc)
 
-  add_executable(arrangement_2
-                 arrangement_2.cpp
-                 ArrangementDemoWindow.cpp
-                 ArrangementDemoTab.cpp
-                 ArrangementDemoGraphicsView.cpp
-                 ArrangementGraphicsItem.cpp
-                 Callback.cpp
-                 VerticalRayShootCallback.cpp
-                 EnvelopeCallback.cpp
-                 SplitEdgeCallback.cpp
-                 FillFaceCallback.cpp
-                 GraphicsViewSegmentInput.cpp
-                 Utils.cpp
-                 NewTabDialog.cpp
-                 OverlayDialog.cpp
-                 ArrangementDemoPropertiesDialog.cpp
-                 AlgebraicCurveInputDialog.cpp
-                 ColorItemEditor.cpp
-                 PropertyValueDelegate.cpp
-                 DeleteCurveMode.cpp
-                 DeleteCurveModeItemEditor.cpp
-                 PointsGraphicsItem.cpp
-                 VerticalRayGraphicsItem.cpp
-                 DeleteCurveCallback.cpp
-                 CurveGraphicsItem.cpp
-                 ArrangementPainterOstream.cpp
-                 GraphicsViewCurveInput.cpp
-                 AlgebraicCurveParser.cpp
-                 ${CGAL_Qt5_MOC_FILES}
-                 ${arrangement_2_uis}
-                 ${CGAL_Qt5_RESOURCE_FILES})
+add_executable(arrangement_2
+               arrangement_2.cpp
+               ArrangementDemoWindow.cpp
+               ArrangementDemoTab.cpp
+               ArrangementDemoGraphicsView.cpp
+               ArrangementGraphicsItem.cpp
+               Callback.cpp
+               VerticalRayShootCallback.cpp
+               EnvelopeCallback.cpp
+               SplitEdgeCallback.cpp
+               FillFaceCallback.cpp
+               GraphicsViewSegmentInput.cpp
+               Utils.cpp
+               NewTabDialog.cpp
+               OverlayDialog.cpp
+               ArrangementDemoPropertiesDialog.cpp
+               AlgebraicCurveInputDialog.cpp
+               ColorItemEditor.cpp
+               PropertyValueDelegate.cpp
+               DeleteCurveMode.cpp
+               DeleteCurveModeItemEditor.cpp
+               PointsGraphicsItem.cpp
+               VerticalRayGraphicsItem.cpp
+               DeleteCurveCallback.cpp
+               CurveGraphicsItem.cpp
+               ArrangementPainterOstream.cpp
+               GraphicsViewCurveInput.cpp
+               AlgebraicCurveParser.cpp
+               ${CGAL_Qt5_MOC_FILES}
+               ${arrangement_2_uis}
+               ${CGAL_Qt5_RESOURCE_FILES})
 
-  qt5_use_modules(arrangement_2 Core Gui Widgets Script)
-  target_link_libraries(arrangement_2 CGAL::CGAL CGAL::CGAL_Qt5 CGAL::CGAL_Core)
-  add_to_cached_list(CGAL_EXECUTABLE_TARGETS arrangement_2)
+qt5_use_modules(arrangement_2 Core Gui Widgets Script)
+target_link_libraries(arrangement_2 CGAL::CGAL CGAL::CGAL_Qt5 CGAL::CGAL_Core)
+add_to_cached_list(CGAL_EXECUTABLE_TARGETS arrangement_2)
 
-  include(${CGAL_MODULES_DIR}/CGAL_add_test.cmake)
-  cgal_add_compilation_test(arrangement_2)
-else()
-  message(STATUS "NOTICE: This demo requires CGAL, CGAL-Core and Qt5, and will not be compiled.")
-endif()
+include(${CGAL_MODULES_DIR}/CGAL_add_test.cmake)
+cgal_add_compilation_test(arrangement_2)