diff --git a/src/buttons.c b/src/buttons.c
index e726a0b4..0d37214d 100644
--- a/src/buttons.c
+++ b/src/buttons.c
@@ -4493,7 +4493,8 @@ void Display_effect_states(void)
   Display_effect_state(C2+23, 81, "Grid"   ,Snap_mode);
   Display_effect_state(C2+23,100, "Tiling" ,Tiling_mode);
 
-  Display_effect_state(177+23,24, "8 bit" ,Constraint_mode);
+  Display_effect_state(177+23,24, "8 bit"  ,Constraint_mode);
+  Display_effect_state(177+23,43, "Tilemap",Tilemap_mode);
 }
 
 
@@ -4526,6 +4527,7 @@ void Button_Effects(void)
   Window_set_normal_button( 83,131,104,14,"Feedback:   ",1,1,SDLK_f); // 13
 
   Window_set_normal_button(177, 19, 16,16,"",0,1,Config_Key[SPECIAL_FORMAT_CHECKER_MENU][0]); // 14
+  Window_set_normal_button(177, 38, 16,16,"",0,1,KEY_NONE); // 15
 
   Display_feedback_state();
   Display_effect_sprite(EFFECTS_SPRITE_SHADE,   8,20);
@@ -4590,6 +4592,9 @@ void Button_Effects(void)
         case 10:
           Window_help(BUTTON_EFFECTS, "TILING");
           break;
+        case 15:
+          Window_help(BUTTON_EFFECTS, "TILEMAP");
+          break;        
         default:
           Window_help(BUTTON_EFFECTS, NULL);
       }
@@ -4782,6 +4787,12 @@ void Button_Effects(void)
           clicked_button = 11;
         }
         break;
+      case 15: // Tilemap
+          Button_Tilemap_mode();
+          Hide_cursor();
+          Display_effect_state(177+23,43, "Tilemap" ,Tilemap_mode);
+          Display_cursor();
+        break;
     }
   }
   while (clicked_button!=11);
@@ -4791,7 +4802,7 @@ void Button_Effects(void)
   else
     Hide_cursor();
 
-  if (!(Shade_mode||Quick_shade_mode||Colorize_mode||Smooth_mode||Tiling_mode||Smear_mode||Stencil_mode||Mask_mode||Sieve_mode||Snap_mode||Constraint_mode))
+  if (!(Shade_mode||Quick_shade_mode||Colorize_mode||Smooth_mode||Tiling_mode||Smear_mode||Stencil_mode||Mask_mode||Sieve_mode||Snap_mode||Constraint_mode||Tilemap_mode))
     Unselect_button(BUTTON_EFFECTS);
 
   Display_cursor();
diff --git a/src/buttons.h b/src/buttons.h
index 4a755f5c..6562b909 100644
--- a/src/buttons.h
+++ b/src/buttons.h
@@ -441,6 +441,9 @@ void Button_Tiling_menu(void);
 void Button_Constraint_mode(void);
 void Button_Constraint_menu(void);
 
+void Button_Tilemap_mode(void);
+void Button_Tilemap_menu(void);
+
 /*!
     Callback for the command that turns off all drawaing effects.
 */
diff --git a/src/buttons_effects.c b/src/buttons_effects.c
index ec5666c2..ed22df6f 100644
--- a/src/buttons_effects.c
+++ b/src/buttons_effects.c
@@ -189,6 +189,16 @@ void Button_Constraint_menu(void)
 
 }
 
+// Tilemap mode
+void Button_Tilemap_mode(void)
+{
+  Tilemap_mode=!Tilemap_mode;
+}
+
+void Button_Tilemap_menu(void)
+{
+
+}
 
 //--------------------------------- Stencil ----------------------------------
 void Button_Stencil_mode(void)
diff --git a/src/global.h b/src/global.h
index 8aa18abd..191258cd 100644
--- a/src/global.h
+++ b/src/global.h
@@ -726,9 +726,19 @@ GFX2_GLOBAL byte Mask_mode;
 /// Array of booleans. True if the indexed color is protected by the mask.
 GFX2_GLOBAL byte Mask_table[256];
 
-// -- Constraint enforcer
+// -- Constraint mode
+
+/// Constraint enforcer
 GFX2_GLOBAL byte Constraint_mode;
 
+// -- Tilemap mode
+
+/// Tilemap mode
+GFX2_GLOBAL byte Tilemap_mode;
+
+/// Tilemap allows swapped tiles : 0:No 1:Horizontal 2:Vertical 3:Both 
+GFX2_GLOBAL byte Tilemap_allow_swap;
+
 // -- Magnifier data
 
 #ifdef GLOBAL_VARIABLES