diff --git a/Heimdall.lua b/Heimdall.lua
index f901173..835decb 100644
--- a/Heimdall.lua
+++ b/Heimdall.lua
@@ -31,6 +31,7 @@ local function init()
     ---@field GetOrDefault fun(table: table<any, any>, keys: string[], default: any): any
     ---@field Split fun(input: string, deliminer: string): string[]
     ---@field IsStinky fun(name: string): boolean
+    ---@field Memoize fun(f: function): function
     ---@field WhoQueryService WhoQueryService
     ---@field Whoer InitTable
     ---@field Messenger InitTable
@@ -88,6 +89,7 @@ local function init()
     ---@field notes table<string, Note[]>
     ---@field locale string
     ---@field echoToRussian boolean
+    ---@field debug boolean
 
     ---@class HeimdallSpotterConfig
     ---@field enabled boolean
@@ -315,6 +317,7 @@ local function init()
 
     --/run Heimdall_Data.config.who.queries="g-\"БеспредеЛ\"|ally"
     Heimdall_Data.config = {
+        debug = shared.GetOrDefault(Heimdall_Data, { "config", "debug" }, false),
         spotter = {
             enabled = shared.GetOrDefault(Heimdall_Data, { "config", "spotter", "enabled" }, true),
             debug = shared.GetOrDefault(Heimdall_Data, { "config", "spotter", "debug" }, false),
@@ -622,6 +625,33 @@ local function init()
         return Heimdall_Data.config.stinkies[name] ~= nil or shared.StinkyCache[name] ~= nil
     end
 
+    ---@param f function
+    ---@return function
+    shared.Memoize = function(f)
+        local mem = {}                       -- memoizing table
+        setmetatable(mem, { __mode = "kv" }) -- make it weak
+        return function(x)                   -- new version of ’f’, with memoizing
+            if Heimdall_Data.config.debug then
+                print(string.format("[Heimdall] Memoize %s", tostring(x)))
+            end
+            local r = mem[x]
+            if r == nil then -- no previous result?
+                if Heimdall_Data.config.debug then
+                    print(string.format("[Heimdall] Memoize %s is nil, calling original function", tostring(x)))
+                end
+                r = f(x) -- calls original function
+                if Heimdall_Data.config.debug then
+                    print(string.format("[Heimdall] Memoized result for %s: %s", tostring(x), tostring(r)))
+                end
+                mem[x] = r -- store result for reuse
+            end
+            if Heimdall_Data.config.debug then
+                print(string.format("[Heimdall] Memoize %s is %s", tostring(x), tostring(r)))
+            end
+            return r
+        end
+    end
+
     shared.Messenger.Init()
     shared.StinkyTracker.Init()
     shared.AgentTracker.Init()
diff --git a/Modules/Config.lua b/Modules/Config.lua
index 2d8f365..0177269 100644
--- a/Modules/Config.lua
+++ b/Modules/Config.lua
@@ -530,7 +530,16 @@ function shared.Config.Init()
     configFrame:Add(scale, 2, 2)
     local title = configFrame.frame:CreateFontString(nil, "ARTWORK", "GameFontNormal")
     title:SetText(string.format("%s - v%s", shared.L[Heimdall_Data.config.locale].config.heimdallConfig, shared.VERSION))
-    configFrame:Add(title, 2, 8)
+    configFrame:Add(title, 2, 7)
+
+    local debug = CreateBasicButton("HeimdallConfigDebug", configFrame.frame,
+        shared.L[Heimdall_Data.config.locale].config.debug, function()
+        Heimdall_Data.config.debug = not Heimdall_Data.config.debug
+        return Heimdall_Data.config.debug
+    end)
+    debug:UpdateColor(Heimdall_Data.config.debug)
+    configFrame:Add(debug, 2, 1)
+
     local russian = nil
     local english = CreateBasicButton("HeimdallConfigEnglish", configFrame.frame, shared.L.en.config.english, function()
         Heimdall_Data.config.locale = "en"
diff --git a/Modules/Whoer.lua b/Modules/Whoer.lua
index be5b284..0770b8f 100644
--- a/Modules/Whoer.lua
+++ b/Modules/Whoer.lua
@@ -169,7 +169,7 @@ function shared.Whoer.Init()
 			return nil
 		end,
 		---@param query WHOQuery
-		---@return string	
+		---@return string
 		WhoQueryToString = function(query)
 			local ret = ""
 			ret = ret .. query.query
@@ -226,6 +226,26 @@ function shared.Whoer.Init()
 	}
 	shared.WhoQueryService.queries = shared.WhoQueryService.WhoQueriesFromString(Heimdall_Data.config.who.queries)
 
+	---@param inputZone string
+	---@return boolean
+	local ShouldNotifyForZone = shared.Memoize(function(inputZone)
+		if not Heimdall_Data.config.who.debug then
+			print(string.format("[%s] ShouldNotifyForZone %s", ModuleName, inputZone))
+		end
+		for zone, _ in pairs(Heimdall_Data.config.who.zoneNotifyFor) do
+			if string.find(inputZone, zone) then
+				if not Heimdall_Data.config.who.debug then
+					print(string.format("[%s] ShouldNotifyForZone %s is true thanks to %s", ModuleName, inputZone, zone))
+				end
+				return true
+			end
+		end
+		if not Heimdall_Data.config.who.debug then
+			print(string.format("[%s] ShouldNotifyForZone %s is false", ModuleName, inputZone))
+		end
+		return false
+	end)
+
 	-----@type WHOQuery[]
 	--local whoQueries = {
 	--	WHOQuery.new("g-\"БеспредеЛ\"", {}),
@@ -271,7 +291,8 @@ function shared.Whoer.Init()
 			return string.format("Cannot notify for nil player %s", tostring(player))
 		end
 
-		if not Heimdall_Data.config.who.zoneNotifyFor[player.zone] then
+		if not ShouldNotifyForZone(player.zone) then
+			--if not Heimdall_Data.config.who.zoneNotifyFor[player.zone] then
 			if Heimdall_Data.config.who.debug then
 				print(string.format("[%s] Skipping notification - Zone '%s' not in notify list", ModuleName, player.zone))
 			end
@@ -341,8 +362,9 @@ function shared.Whoer.Init()
 	local function NotifyZoneChanged(player, zone)
 		if not Heimdall_Data.config.who.enabled then return end
 		if not player then return string.format("Cannot notify for nil player %s", tostring(player)) end
-		if not Heimdall_Data.config.who.zoneNotifyFor[zone]
-			and not Heimdall_Data.config.who.zoneNotifyFor[player.zone] then
+		--if not Heimdall_Data.config.who.zoneNotifyFor[zone]
+		--	and not Heimdall_Data.config.who.zoneNotifyFor[player.zone] then
+		if not ShouldNotifyForZone(zone) and not ShouldNotifyForZone(player.zone) then
 			return string.format("Not notifying for zones %s and %s", tostring(zone), tostring(player.zone))
 		end
 		local text = string.format(shared.L.en.whoerMoved,
@@ -405,9 +427,9 @@ function shared.Whoer.Init()
 	local function NotifyGone(player)
 		if not Heimdall_Data.config.who.enabled then return end
 		if not player then return string.format("Cannot notify for nil player %s", tostring(player)) end
-		if not Heimdall_Data.config.who.zoneNotifyFor[player.zone] then
-			return string.format("Not notifying for zone %s",
-				tostring(player.zone))
+		--if not Heimdall_Data.config.who.zoneNotifyFor[player.zone] then
+		if not ShouldNotifyForZone(player.zone) then
+			return string.format("Not notifying for zone %s", tostring(player.zone))
 		end
 
 		local text = string.format(shared.L.en.whoerGone,
@@ -517,6 +539,10 @@ function shared.Whoer.Init()
 					print(string.format("[%s] Ignoring blacklisted player: %s", ModuleName, name))
 				end
 				continue = true
+			else
+				if Heimdall_Data.config.who.debug then
+					print(string.format("[%s] Player %s is not blacklisted", ModuleName, name))
+				end
 			end
 
 			if not continue then
@@ -572,6 +598,9 @@ function shared.Whoer.Init()
 
 				player.lastSeenInternal = GetTime()
 				if player.zone ~= zone then
+					if Heimdall_Data.config.who.debug then
+						print(string.format("[%s] Player %s zone changed from %s to %s", ModuleName, name, player.zone, zone))
+					end
 					local err = NotifyZoneChanged(player, zone)
 					if err then
 						print(string.format("Error notifying for %s: %s", tostring(name), tostring(err)))