--- a/Framework/Radiography/RadiographyScene.h	Tue Feb 19 11:40:14 2019 +0100
+++ b/Framework/Radiography/RadiographyScene.h	Wed Feb 20 20:57:43 2019 +0100
@@ -174,6 +174,30 @@
 
     const RadiographyLayer& GetLayer(size_t layerIndex) const;
 
+    template <typename TypeLayer>
+    TypeLayer* GetLayer(size_t index = 0)
+    {
+      std::vector<size_t> layerIndexes;
+      GetLayersIndexes(layerIndexes);
+
+      size_t count = 0;
+
+      for (size_t i = 0; i < layerIndexes.size(); ++i)
+      {
+        TypeLayer* typedLayer = dynamic_cast<TypeLayer*>(layers_[layerIndexes[i]]);
+        if (typedLayer != NULL)
+        {
+          if (count == index)
+          {
+            return typedLayer;
+          }
+          count++;
+        }
+      }
+
+      return NULL;
+    }
+
     void GetLayersIndexes(std::vector<size_t>& output) const;
 
     Extent2D GetSceneExtent() const;

--- a/Framework/Radiography/RadiographyWidget.cpp	Tue Feb 19 11:40:14 2019 +0100
+++ b/Framework/Radiography/RadiographyWidget.cpp	Wed Feb 20 20:57:43 2019 +0100
@@ -25,6 +25,7 @@
 #include <Core/Images/Image.h>
 #include <Core/Images/ImageProcessing.h>
 
+#include "RadiographyMaskLayer.h"
 
 namespace OrthancStone
 {
@@ -194,6 +195,28 @@
     selectedLayer_ = layer;
   }
 
+  bool RadiographyWidget::SelectMaskLayer(size_t index)
+  {
+    std::vector<size_t> layerIndexes;
+    size_t count = 0;
+    scene_->GetLayersIndexes(layerIndexes);
+
+    for (size_t i = 0; i < layerIndexes.size(); ++i)
+    {
+      const RadiographyMaskLayer* maskLayer = dynamic_cast<const RadiographyMaskLayer*>(&(scene_->GetLayer(layerIndexes[i])));
+      if (maskLayer != NULL)
+      {
+        if (count == index)
+        {
+          Select(layerIndexes[i]);
+          return true;
+        }
+        count++;
+      }
+    }
+
+    return false;
+  }
 
   bool RadiographyWidget::LookupSelectedLayer(size_t& layer)
   {

--- a/Framework/Radiography/RadiographyWidget.h	Tue Feb 19 11:40:14 2019 +0100
+++ b/Framework/Radiography/RadiographyWidget.h	Wed Feb 20 20:57:43 2019 +0100
@@ -27,6 +27,8 @@
 
 namespace OrthancStone
 {
+  class RadiographyMaskLayer;
+
   class RadiographyWidget :
     public WorldSceneWidget,
     public IObserver
@@ -76,6 +78,8 @@
 
     void Select(size_t layer);
 
+    bool SelectMaskLayer(size_t index = 0);
+
     bool LookupSelectedLayer(size_t& layer);
 
     void OnGeometryChanged(const RadiographyScene::GeometryChangedMessage& message);

--- a/README	Tue Feb 19 11:40:14 2019 +0100
+++ b/README	Wed Feb 20 20:57:43 2019 +0100
@@ -125,6 +125,20 @@
 ./OrthancStoneSimpleViewer --studyId=XX
 ``` 
 
+to build the Qt native samples on Windows:
+-----------------------------------------
+
+In a VS2015 x64 Native Tools Command Prompt:
+
+```
+mkdir -p C:\Users\alain\osimis\builds\orthanc-stone-build
+cd C:\Users\alain\osimis\builds\orthanc-stone-build
+cmake -G Ninja -DSTATIC_BUILD=ON -DORTHANC_FRAMEWORK_SOURCE=path -DORTHANC_FRAMEWORK_ROOT=C:\Users\alain\osimis\orthanc -DCMAKE_PREFIX_PATH=C:\Qt\5.9.3\msvc2015_64 ..\..\orthanc-stone\Applications\Samples
+
+cmake -G Ninja -DALLOW_DOWNLOADS=ON -DENABLE_QT=ON ~/orthanc-stone/Applications/Samples/
+cmake --build . --target OrthancStoneSimpleViewer -- -j 5
+```
+
 
 Licensing
 ---------