Only add the string if needed

diff --git a/Localization.lua b/Localization.lua
index ca33d0b..8bad8c8 100644
--- a/Localization.lua
+++ b/Localization.lua
@@ -1,7 +1,16 @@
 local _, L = ...

+local FilterDetailsTooltip = [[
+Easily add more items to filter by
+grabbing one from your inventory
+and dropping it into the box below.
+
+Just as easily you remove an existing
+item by right-clicking on it.
+]]
+
 setmetatable(L, {__index = function(L, key)
-	local value = tostring(key)
+	local value = key == 'FilterDetailsTooltip' and FilterDetailsTooltip or tostring(key)
 	L[key] = value
 	return value
 end})
@@ -9,14 +18,3 @@ end})
 L['ALT key'] = ALT_KEY
 L['CTRL key'] = CTRL_KEY
 L['SHIFT key'] = SHIFT_KEY
-
-L.FilterDetailsTooltip = [[
-Easily add more items to filter by
-grabbing one from your inventory
-and dropping it into the box below.
-
-Just as easily you remove an existing
-item by right-clicking on it.
-
-This only works with items that starts quests.
-]]