diff --git a/lib/Properties.hs b/lib/Properties.hs
index a2a84d6c4eaf4a404435cb269f1f1868664a5725..605f970760b519d72e9a20bdd5675163f34f5267 100644
--- a/lib/Properties.hs
+++ b/lib/Properties.hs
@@ -423,7 +423,7 @@ checkTileThing removeExits p@(Property name _value) = case name of
       requireProperty "openWebsiteTrigger"
     "url" -> complain "the property \"url\" defining embedded iframes must be \
                       \set on an object in an objectgroup layer."
-    "exitUrl" -> if removeExits
+    "exitUrl" -> if not removeExits
       then do
         forbidEmptyLayer
         unwrapURI (Proxy @"map") p