diff --git a/app-proto/src/display.rs b/app-proto/src/display.rs
index 68f4b1b..21c7f86 100644
--- a/app-proto/src/display.rs
+++ b/app-proto/src/display.rs
@@ -22,6 +22,9 @@ use crate::{
 
 // --- scene data ---
 
+const COLOR_SIZE: usize = 3;
+type ColorWithOpacity = [f32; COLOR_SIZE + 1];
+
 struct SceneSpheres {
     representations: Vec<DVector<f64>>,
     colors: Vec<ElementColor>,
@@ -53,7 +56,7 @@ impl SceneSpheres {
 
 struct ScenePoints {
     representations: Vec<DVector<f64>>,
-    colors: Vec<ElementColor>,
+    colors_with_opacity: Vec<ColorWithOpacity>,
     highlights: Vec<f32>,
     selections: Vec<f32>
 }
@@ -62,15 +65,19 @@ impl ScenePoints {
     fn new() -> ScenePoints {
         ScenePoints {
             representations: Vec::new(),
-            colors: Vec::new(),
+            colors_with_opacity: Vec::new(),
             highlights: Vec::new(),
             selections: Vec::new()
         }
     }
     
-    fn push(&mut self, representation: DVector<f64>, color: ElementColor, highlight: f32, selected: bool) {
+    fn push(&mut self, representation: DVector<f64>, color: ElementColor, opacity: f32, highlight: f32, selected: bool) {
+        let mut color_with_opacity = [0.0; COLOR_SIZE + 1];
+        color_with_opacity[..COLOR_SIZE].copy_from_slice(&color);
+        color_with_opacity[COLOR_SIZE] = opacity;
+        
         self.representations.push(representation);
-        self.colors.push(color);
+        self.colors_with_opacity.push(color_with_opacity);
         self.highlights.push(highlight);
         self.selections.push(if selected { 1.0 } else { 0.0 });
     }
@@ -156,11 +163,15 @@ impl DisplayItem for Sphere {
 
 impl DisplayItem for Point {
     fn show(&self, scene: &mut Scene, selected: bool) {
-        const HIGHLIGHT: f32 = 0.5; /* SCAFFOLDING */
+        /* SCAFFOLDING */
+        const GHOST_OPACITY: f32 = 0.4;
+        const HIGHLIGHT: f32 = 0.5;
+        
         let representation = self.representation.get_clone_untracked();
         let color = if selected { self.color.map(|channel| 0.2 + 0.8*channel) } else { self.color };
+        let opacity = if self.ghost.get() { GHOST_OPACITY } else { 1.0 };
         let highlight = if selected { 1.0 } else { HIGHLIGHT };
-        scene.points.push(representation, color, highlight, selected);
+        scene.points.push(representation, color, opacity, highlight, selected);
     }
     
     /* SCAFFOLDING */
@@ -714,7 +725,7 @@ pub fn Display() -> View {
                     // bind them to the corresponding attributes in the vertex
                     // shader
                     bind_new_buffer_to_attribute(&ctx, point_position_attr, SPACE_DIM as i32, point_positions.as_slice());
-                    bind_new_buffer_to_attribute(&ctx, point_color_attr, COLOR_SIZE as i32, scene.points.colors.concat().as_slice());
+                    bind_new_buffer_to_attribute(&ctx, point_color_attr, (COLOR_SIZE + 1) as i32, scene.points.colors_with_opacity.concat().as_slice());
                     bind_new_buffer_to_attribute(&ctx, point_highlight_attr, 1 as i32, scene.points.highlights.as_slice());
                     bind_new_buffer_to_attribute(&ctx, point_selection_attr, 1 as i32, scene.points.selections.as_slice());
                     
diff --git a/app-proto/src/point.frag b/app-proto/src/point.frag
index 3a361a8..194a072 100644
--- a/app-proto/src/point.frag
+++ b/app-proto/src/point.frag
@@ -2,7 +2,7 @@
 
 precision highp float;
 
-in vec3 point_color;
+in vec4 point_color;
 in float point_highlight;
 in float total_radius;
 
@@ -13,6 +13,7 @@ void main() {
     
     const float POINT_RADIUS = 4.;
     float border = smoothstep(POINT_RADIUS - 1., POINT_RADIUS, r);
-    vec3 color = mix(point_color, vec3(1.), border * point_highlight);
-    outColor = vec4(color, 1. - smoothstep(total_radius - 1., total_radius, r));
+    float disk = 1. - smoothstep(total_radius - 1., total_radius, r);
+    vec4 color = mix(point_color, vec4(1.), border * point_highlight);
+    outColor = vec4(vec3(1.), disk) * color;
 }
\ No newline at end of file
diff --git a/app-proto/src/point.vert b/app-proto/src/point.vert
index 6945010..0b76bc1 100644
--- a/app-proto/src/point.vert
+++ b/app-proto/src/point.vert
@@ -1,11 +1,11 @@
 #version 300 es
 
 in vec4 position;
-in vec3 color;
+in vec4 color;
 in float highlight;
 in float selected;
 
-out vec3 point_color;
+out vec4 point_color;
 out float point_highlight;
 out float total_radius;