Stairs+ nodes are not in wood and stone groups anymore to not make them usable in crafting.

stairsplus/registrations.lua

@@ -29,7 +29,11 @@ for _, name in pairs(default_nodes) do
 	local nodename = "default:"..name
 	local ndef = minetest.registered_nodes[nodename]
 	local groups = {}
-	for k, v in pairs(ndef.groups) do groups[k] = v end
+	for k, v in pairs(ndef.groups)
+		do if k ~= "wood" and k ~= "stone" then -- Ignore wood and stone groups to not make them usable in crafting.
+			groups[k] = v
+		end
+	end
 	local drop
 	if type(ndef.drop) == "string" then
 		drop = ndef.drop:sub(9)