diff --git a/technic/machines/other/constructor.lua b/technic/machines/other/constructor.lua
index 7cf2856..d99788e 100644
--- a/technic/machines/other/constructor.lua
+++ b/technic/machines/other/constructor.lua
@@ -146,14 +146,15 @@ local function make_constructor(mark, length)
 		on_construct = function(pos)
 			local meta = minetest.get_meta(pos)
 			local formspec = "size[8,9;]"..
-				"label[0,0;"..S("Constructor Mk%d"):format(mark).."]"..
-				"list[current_player;main;0,5;8,4;]"
+				"label[0,0;"..S("Constructor Mk%d"):format(mark).."]"
 			for i = 1, length do
 				formspec = formspec
 					.."label[5,"..(i - 1)..";"..S("Slot %d"):format(i).."]"
 					.."list[current_name;slot"..i
 						..";6,"..(i - 1)..";1,1;]"
 			end
+			formspec = formspec .. "list[current_player;main;0,5;8,4;]"
+			if 1 == mark then formspec = formspec .. "listring[]" end
 			meta:set_string("formspec", formspec)
 			meta:set_string("infotext", S("Constructor Mk%d"):format(mark))
 			local inv = meta:get_inventory()
@@ -205,3 +206,4 @@ end
 make_constructor(1, 1)
 make_constructor(2, 2)
 make_constructor(3, 4)
+