diff --git a/misc.c b/misc.c
index d48cf531..4abf635f 100644
--- a/misc.c
+++ b/misc.c
@@ -46,25 +46,31 @@
 word Count_used_colors(dword* usage)
 {
   int nb_pixels = 0;
-  Uint8* current_pixel = Main_screen;
+  Uint8* current_pixel;
   Uint8 color;
   word nb_colors = 0;
   int i;
+  int layer;
 
   for (i = 0; i < 256; i++) usage[i]=0;
 
   // Compute total number of pixels in the picture
   nb_pixels = Main_image_height * Main_image_width;
 
-  // For each pixel in picture
-  for (i = 0; i < nb_pixels; i++)
+  // For each layer
+  for (layer = 0; layer < Main_backups->Pages->Nb_layers; layer++)
   {
-    color=*current_pixel; // get color in picture for this pixel
-
-    usage[color]++; // add it to the counter
-
-    // go to next pixel
-    current_pixel++;
+    current_pixel = Main_backups->Pages->Image[layer];
+    // For each pixel in picture
+    for (i = 0; i < nb_pixels; i++)
+    {
+      color=*current_pixel; // get color in picture for this pixel
+  
+      usage[color]++; // add it to the counter
+  
+      // go to next pixel
+      current_pixel++;
+    }
   }
 
   // count the total number of unique used colors
diff --git a/palette.c b/palette.c
index 4236a006..a4456d5e 100644
--- a/palette.c
+++ b/palette.c
@@ -1838,7 +1838,7 @@ void Button_Palette(void)
           Set_red(i,backup_palette[temp_color].R,working_palette);
           Set_green (i,backup_palette[temp_color].G,working_palette);
           Set_blue (i,backup_palette[temp_color].B,working_palette);
-          if (clicked_button==22)
+          if (clicked_button==21)
           {
             conversion_table[i]=temp_color;
             conversion_table[temp_color]=i;
@@ -1850,7 +1850,7 @@ void Button_Palette(void)
         }
         Draw_all_palette_sliders(red_slider,green_slider,blue_slider,working_palette,block_start,block_end);
         // Si on est en X-Invert, on remap l'image (=> on fait aussi 1 backup)
-        if (clicked_button==22)
+        if (clicked_button==21)
         {
           if (!image_is_backed_up)
           {