diff --git a/lib/ace/commands/incremental_search_commands.js b/lib/ace/commands/incremental_search_commands.js
index f0514947..986fb56e 100644
--- a/lib/ace/commands/incremental_search_commands.js
+++ b/lib/ace/commands/incremental_search_commands.js
@@ -161,11 +161,11 @@ oop.inherits(IncrementalSearchKeyboardHandler, HashHandler);
                        + ", keyCode: " + keyCode);
         var cmd = handleKeyboard$super.call(this, data, hashId, key, keyCode);
         if (cmd.command) { return cmd; }
-        if (key.length === 1 && !(/[\x00-\x1F]/.test(key))) {
+        if (hashId == -1) {
             var extendCmd = this.commands.extendSearchTerm;
             if (extendCmd) { return {command: extendCmd, args: key}; }
         }
-        return {command: "null"};
+        return {command: "null", passEvent: hashId == 0 || hashId == 4};
     }
 
 }).call(IncrementalSearchKeyboardHandler.prototype);