diff --git a/src/js/3p-filters.js b/src/js/3p-filters.js
index 74a885c2c..1d80d803d 100644
--- a/src/js/3p-filters.js
+++ b/src/js/3p-filters.js
@@ -368,7 +368,7 @@ const hashFromCurrentFromSettings = function() {
     hash.push(
         listHash.sort().join(),
         qs$('#importLists').checked &&
-            reValidExternalList.test(qs$('#externalLists').value),
+            reValidExternalList.test(qs$('#externalLists').value.trim()),
         qs$('#lists .listEntry.toRemove') !== null
     );
     return hash.join();