diff --git a/bitplane-thingie.p8 b/bitplane-thingie.p8
index 2ea83a4..0711b0c 100644
--- a/bitplane-thingie.p8
+++ b/bitplane-thingie.p8
@@ -109,14 +109,14 @@ function draw_ui()
  print("clr", 18, 117, 7) 
  -- draw "color" bits
  for i=0,3 do
-  draw_ui_checkbox(32 + 9*i, plane_mask & 1<<i ~= 0,i)
+  draw_ui_checkbox(32 + 9*i, plane_mask & 1<<(i+4) ~= 0,i)
  end
  
  print("mask", 73, 118, 1)
  print("mask", 72, 117, 7)
  -- draw "mask" bits
  for i=0,3 do
-  draw_ui_checkbox(90 + 9*i, plane_mask & 1<<(i+4) ~= 0, i)
+  draw_ui_checkbox(90 + 9*i, plane_mask & 1<<i ~= 0, i)
  end
 end
 
@@ -146,7 +146,7 @@ function handle_ui_click(x, y)
   local box = x \ 9
   --check range
   if (box < 0 or box > 3) return
-  toggle_mask_bit(box)
+  toggle_mask_bit(box+4)
   return
  end
  
@@ -155,7 +155,7 @@ function handle_ui_click(x, y)
  local box = x \ 9
  --check range
  if (box < 0 or box > 3) return
- toggle_mask_bit(box + 4)
+ toggle_mask_bit(box)
  return
 end