Properly filter flag 23 and spew errors for everything else

diff --git a/Collie.lua b/Collie.lua
index 1cc12b6..e3f7f63 100644
--- a/Collie.lua
+++ b/Collie.lua
@@ -5,7 +5,6 @@ local filterFlags = {
 	['flying'] = true,
 	['ground'] = true,
 	['combined'] = true,
-	['unknown'] = true,
 }

 local Search = CreateFrame('EditBox', 'MountSearch', MountJournal, 'SearchBoxTemplate')
@@ -33,10 +32,10 @@ local function BuildMounts(self, event)
 			mounts[index] = 'flying'
 		elseif(flag == 29) then
 			mounts[index] = 'ground'
-		elseif(flag == 31) then
+		elseif(flag == 31 or flag == 23) then
 			mounts[index] = 'combined'
 		else
-			mounts[index] = 'unknown'
+			print(string.format('|cff33ff99Collie:|r [%s] is not added, let the author of this addon know!', name))
 		end

 		-- exceptions
@@ -167,15 +166,6 @@ local function CreateDropDown()
 		MountJournal_UpdateMountList()
 	end
 	UIDropDownMenu_AddButton(info)
-
-	info.text = 'Unknown'
-	info.checked = filterFlags.unknown
-	info.func = function(...)
-		local _, _, _, enabled = ...
-		filterFlags.unknown = enabled
-		MountJournal_UpdateMountList()
-	end
-	UIDropDownMenu_AddButton(info)
 end

 local FilterDropDown = CreateFrame('Frame')