diff --git a/platform/firefox/vapi-background.js b/platform/firefox/vapi-background.js
index 3b8a1a7ec..b5901ec8b 100644
--- a/platform/firefox/vapi-background.js
+++ b/platform/firefox/vapi-background.js
@@ -3435,19 +3435,14 @@ vAPI.commands = (function() {
 
         var myKey, shortcut, parts, modifiers, key;
         for ( var command of commands ) {
+            modifiers = key = '';
             shortcut = vAPI.localStorage.getItem('shortcuts.' + command.id);
             if ( shortcut === null ) {
                 vAPI.localStorage.setItem('shortcuts.' + command.id, '');
+            } else if ( (parts = /^((?:[a-z]+-){1,})?(\w)$/.exec(shortcut)) !== null ) {
+                modifiers = (parts[1] || '').slice(0, -1).replace(/-/g, ',');
+                key = parts[2] || '';
             }
-            if ( typeof shortcut !== 'string' ) { continue; }
-            parts = /^((?:[a-z]+-){1,})?(\w)$/.exec(shortcut);
-            if ( parts === null ) { continue; }
-            modifiers = parts[1];
-            if ( typeof modifiers === 'string' ) {
-                modifiers = parts[1].slice(0, -1).split('-').join(' ');
-            }
-            key = parts[2];
-            if ( typeof key !== 'string' ) { continue; }
             myKey = doc.createElement('key');
             myKey.setAttribute('id', 'uBlock0Key-' + command.id);
             if ( modifiers !== '' ) {