diff --git a/src/app/editor.rs b/src/app/editor.rs
index 5d2d93f..4aa7f53 100644
--- a/src/app/editor.rs
+++ b/src/app/editor.rs
@@ -2,10 +2,11 @@ use clap::{App, crate_version};
 
 use sfml::system::Vector2;
 use sfml::window::{Event, Key};
+use sfml::window::mouse::Button;
 use sfml::graphics::{RectangleShape, RenderTarget, Transformable, Color, Shape};
 
 use rusty::engine::renderer::Renderer;
-use rusty::engine::map::{GraphicTile, Map};
+use rusty::engine::map::{GraphicTile, CollisionTile, Map};
 
 fn main() {
     let _ = App::new("Rusty Editor")
@@ -16,9 +17,12 @@ fn main() {
 
     let mut running = true;
 
-    let map = Map::from_str(include_str!("../../assets/levels/level2.txt")).unwrap();
+    let mut map = Map::from_str(include_str!("../../assets/levels/level2.txt")).unwrap();
 
     loop {
+        let top_panel_size = Vector2::new(renderer.window().size().x as f32, 50.0);
+        let left_panel_size = Vector2::new(100.0, renderer.window().size().y as f32 - top_panel_size.y);
+
         // Manage the events
         while let Some(event) = renderer.poll_event() {
             match event {
@@ -30,6 +34,22 @@ fn main() {
                     code: Key::Escape, ..
                 } => running = false,
 
+                // A click on the screen
+                Event::MouseButtonPressed {
+                    button: Button::Left, x, y,
+                } => {
+                    if x as f32 >= left_panel_size.x && y as f32 >= top_panel_size.y {
+                        let x = ((x - left_panel_size.x as i32) / 16) as usize;
+                        let y = ((y - top_panel_size.y as i32) / 16) as usize;
+
+                        if map.tile(y, x) == CollisionTile::empty() {
+                            map.set_tile(y, x, CollisionTile::full());
+                        } else {
+                            map.set_tile(y, x, CollisionTile::empty());
+                        }
+                    }
+                },
+
                 _ => (),
             }
         }
@@ -38,13 +58,11 @@ fn main() {
         renderer.clear();
 
         // Show the top panel
-        let top_panel_size = Vector2::new(renderer.window().size().x as f32, 50.0);
         let mut top_panel = RectangleShape::with_size(top_panel_size);
         top_panel.set_fill_color(&Color::rgb(255, 0, 0));
         renderer.window_mut().draw(&top_panel);
 
         // Show the left panel
-        let left_panel_size = Vector2::new(100.0, renderer.window().size().y as f32 - top_panel_size.y);
         let mut left_panel = RectangleShape::with_size(left_panel_size);
         left_panel.set_position((0.0, top_panel_size.y));
         left_panel.set_fill_color(&Color::rgb(0, 255, 0));
diff --git a/src/engine/map/mod.rs b/src/engine/map/mod.rs
index 5de1766..36705c6 100644
--- a/src/engine/map/mod.rs
+++ b/src/engine/map/mod.rs
@@ -109,6 +109,18 @@ pub enum GraphicTile {
 }
 
 impl GraphicTile {
+
+    /// Returns a graphic tile from a collision tile.
+    ///
+    /// This might be ugly for the moment.
+    pub fn from_collision_tile(collision: CollisionTile) -> GraphicTile {
+        if collision == CollisionTile::empty() {
+            GraphicTile::Hidden
+        } else {
+            GraphicTile::Center
+        }
+    }
+
     /// Checks if a graphic tile has a top border.
     pub fn is_top(self) -> bool {
         match self {
@@ -343,6 +355,16 @@ impl Map {
         }
     }
 
+    /// Returns a tile of the map.
+    pub fn tile(&self, i: usize, j: usize) -> CollisionTile {
+        self.tiles[(i, j)].0
+    }
+
+    /// Changes a tile of the map.
+    pub fn set_tile(&mut self, i: usize, j: usize, tile: CollisionTile) {
+        self.tiles[(i, j)] = (tile, GraphicTile::from_collision_tile(tile));
+    }
+
     /// Finds a possible entrance.
     pub fn find_entrance(tiles: &Matrix<(CollisionTile, GraphicTile)>) -> (usize, usize) {
         (tiles.rows() - 5, 1)