diff --git a/README.txt b/README.txt
index d89d374..e34a6a4 100644
--- a/README.txt
+++ b/README.txt
@@ -1,6 +1,6 @@
 ********************************************************************************
 *                                                                              *
-*              Advanced spawning mod (adv_spawning) 0.0.5                      *
+*              Advanced spawning mod (adv_spawning) 0.0.6                      *
 *                                                                              *
 *     URL: http://github.com/sapier/adv_spawning                               *
 *     Author: sapier                                                           *
@@ -191,6 +191,11 @@ Statistics:
 
 Changelog:
 
+0.0.6
+ -add configuration option adv_spawing.debug to show or hide spawner entities
+ -fix quota overflow calculation
+ -add rightclick function to show debug info
+
 0.0.5
  -fix MIN/MAX to always return a number value
  -fix default activity range to use a initial value if not manually configured
diff --git a/init.lua b/init.lua
index 83cb5d6..6607250 100644
--- a/init.lua
+++ b/init.lua
@@ -8,10 +8,10 @@
 --
 -------------------------------------------------------------------------------
 
-local version = "0.0.5"
+local version = "0.0.6"
 
 if adv_spawning ~= nil then
-	minetest.log("error","MOD: adv_spawning requires adv_spawning variable to be available")
+	core.log("error","MOD: adv_spawning requires adv_spawning variable to be available")
 end
 
 --------------------------------------------------------------------------------
@@ -19,7 +19,9 @@ end
 -- -----------------------------------------------------------------------------
 adv_spawning = {}
 
-local adv_modpath = minetest.get_modpath("adv_spawning")
+adv_spawning.debug = core.setting_get("adv_spawning.debug")
+
+local adv_modpath = core.get_modpath("adv_spawning")
 
 dofile (adv_modpath .. "/internal.lua")
 dofile (adv_modpath .. "/spawndef_checks.lua")
diff --git a/internal.lua b/internal.lua
index 09b72c1..d507ca3 100644
--- a/internal.lua
+++ b/internal.lua
@@ -212,8 +212,12 @@ function adv_spawning.global_onstep(dtime)
 			adv_spawning.statistics.session.steps
 
 	--reduce following quota by overtime from last step
-	adv_spawning.quota_left =
-		adv_spawning.MAX(0,adv_spawning.quota_left+adv_spawning.quota_reload)
+	if adv_spawning.quota_left < 0 then
+		adv_spawning.quota_left =
+			adv_spawning.MAX(0,adv_spawning.quota_left + adv_spawning.quota_reload)
+	else
+		adv_spawning.quota_left = adv_spawning.quota_reload
+	end
 
 	if adv_spawning.quota_enter() then
 		adv_spawning.handle_mapgen_spawning()
diff --git a/spawn_seed.lua b/spawn_seed.lua
index 07e61e8..9c12c00 100644
--- a/spawn_seed.lua
+++ b/spawn_seed.lua
@@ -113,6 +113,22 @@ function adv_spawning.seed_activate(self)
 	end
 end
 
+--------------------------------------------------------------------------------
+-- @function [parent=#adv_spawning] on_rightclick
+-- @param self spawner entity
+-- @param clicker (unused)
+--------------------------------------------------------------------------------
+function adv_spawning.on_rightclick(self, clicker)
+	if adv_spawning.debug then
+		print("ADV_SPAWNING: Spawner may spawn following mobs:")
+		local index = 1
+		for key,value in pairs(self.spawning_data) do
+			print(string.format("%3d:",index) .. string.format("%30s ",key) .. string.format("%3d s", value))
+			index = index +1
+		end
+	end
+end
+
 --------------------------------------------------------------------------------
 -- @function [parent=#adv_spawning] seed_initialize
 --------------------------------------------------------------------------------
@@ -121,10 +137,10 @@ function adv_spawning.seed_initialize()
 	local spawner_texture = "adv_spawning_invisible.png^[makealpha:128,0,0^[makealpha:128,128,0"
 	local spawner_collisionbox = { 0.0,0.0,0.0,0.0,0.0,0.0}
 
-	--if debug
+	if adv_spawning.debug then
 		spawner_texture = "adv_spawning_spawner.png"
 		spawner_collisionbox = { -0.5,-0.5,-0.5,0.5,0.5,0.5 }
-	--end
+	end
 
 	minetest.register_entity("adv_spawning:spawn_seed",
 		{
@@ -142,7 +158,8 @@ function adv_spawning.seed_initialize()
 			on_step         = adv_spawning.seed_step,
 			get_staticdata  = function(self)
 									return minetest.serialize(self.spawning_data)
-								end
+								end,
+			on_rightclick   = adv_spawning.on_rightclick
 		}
 	)
 end