diff --git a/Source.cpp b/Source.cpp
index 39d3c2a..ed7957c 100644
--- a/Source.cpp
+++ b/Source.cpp
@@ -456,7 +456,9 @@ float quad_(float x, float y) {
 }
 
 float sin_quad(float x, float y) {
-    return 0.5f + 0.5f * cos( M_PI * CLAMP( ( ( x * x ) + ( y * y ) ), 0.f, 1.f ) );
+    float D = sqrt( ( x * x ) + ( y * y ) );
+    return 0.5f + 0.5f * cos( M_PI * CLAMP( D * sqrt(D), 0.f, 1.f ) );
+//    return 0.5f + 0.5f * cos( M_PI * CLAMP( ( ( x * x ) + ( y * y ) ), 0.f, 1.f ) );
 }
 
 void Source::update(float dt)
@@ -472,7 +474,7 @@ void Source::update(float dt)
         // ADJUST alpha based on MIXING node
         // read position of the mixing node and interpret this as transparency of render output
         glm::vec2 dist = glm::vec2(groups_[View::MIXING]->translation_);
-        // use the prefered transfer function
+        // use the sinusoidal transfer function
         blendingshader_->color = glm::vec4(1.0, 1.0, 1.0, sin_quad( dist.x, dist.y ));
         mixingshader_->color = blendingshader_->color;
 
diff --git a/View.cpp b/View.cpp
index 496930a..1423308 100644
--- a/View.cpp
+++ b/View.cpp
@@ -230,9 +230,7 @@ void View::select(glm::vec2 A, glm::vec2 B)
         }
         // set the selection with list of picked (overlaped) sources
         Mixer::selection().set(selection);
-
     }
-
 }
 
 
@@ -357,6 +355,35 @@ void MixingView::centerSource(Source *s)
 
 }
 
+void MixingView::select(glm::vec2 A, glm::vec2 B)
+{
+    // unproject mouse coordinate into scene coordinates
+    glm::vec3 scene_point_A = Rendering::manager().unProject(A);
+    glm::vec3 scene_point_B = Rendering::manager().unProject(B);
+
+    // picking visitor traverses the scene
+    PickingVisitor pv(scene_point_A, scene_point_B);
+    scene.accept(pv);
+
+    // reset selection
+    Mixer::selection().clear();
+
+    // picking visitor found nodes in the area?
+    if ( !pv.empty()) {
+
+        // create a list of source matching the list of picked nodes
+        SourceList selection;
+        // loop over the nodes and add all sources found.
+        for(std::vector< std::pair<Node *, glm::vec2> >::const_reverse_iterator p = pv.rbegin(); p != pv.rend(); p++){
+            Source *s = Mixer::manager().findSource( p->first );
+            if (s && !s->locked())
+                selection.push_back( s );
+        }
+        // set the selection with list of picked (overlaped) sources
+        Mixer::selection().set(selection);
+    }
+}
+
 void MixingView::selectAll()
 {
     for(auto sit = Mixer::manager().session()->begin();
@@ -433,6 +460,14 @@ std::pair<Node *, glm::vec2> MixingView::pick(glm::vec2 P)
         // capture this pick
         pick = { nullptr, glm::vec2(0.f) };
     }
+    else {
+        // get if a source was picked
+        Source *s = Mixer::manager().findSource(pick.first);
+        if (s != nullptr && s->locked()) {
+            if ( !UserInterface::manager().ctrlModifier() )
+                pick = { nullptr, glm::vec2(0.f) };
+        }
+    }
 
     return pick;
 }
@@ -572,7 +607,9 @@ void MixingView::setAlpha(Source *s)
 //#define CIRCLE_PIXEL_RADIUS 262144.0
 
 float sin_quad_texture(float x, float y) {
-    return 0.5f + 0.5f * cos( M_PI * CLAMP( ( ( x * x ) + ( y * y ) ) / CIRCLE_PIXEL_RADIUS, 0.f, 1.f ) );
+//    return 0.5f + 0.5f * cos( M_PI * CLAMP( ( ( x * x ) + ( y * y ) ) / CIRCLE_PIXEL_RADIUS, 0.f, 1.f ) );
+    float D = sqrt( ( x * x )/ CIRCLE_PIXEL_RADIUS + ( y * y )/ CIRCLE_PIXEL_RADIUS );
+    return 0.5f + 0.5f * cos( M_PI * CLAMP( D * sqrt(D), 0.f, 1.f ) );
 }
 
 uint MixingView::textureMixingQuadratic()
diff --git a/View.h b/View.h
index 2e2de16..95430af 100644
--- a/View.h
+++ b/View.h
@@ -106,6 +106,7 @@ public:
     void resize (int) override;
     int  size () override;
     void centerSource(Source *) override;
+    void select(glm::vec2, glm::vec2) override;
     void selectAll() override;
 
     std::pair<Node *, glm::vec2> pick(glm::vec2) override;