diff --git a/firefox_addon/README.md b/firefox_addon/README.md
index 381ff56..aea9d1e 100644
--- a/firefox_addon/README.md
+++ b/firefox_addon/README.md
@@ -23,6 +23,8 @@ The first thing to do is to populate your database (from your/a password server)
 
 When you're in a login form and you want to use gPass, type your login and fill "@@masterkey" in password field. Then submit and password will automatically be replaced by the one in the database (after addon decrypt it).
 
+You can also type "@_masterkey" to only replace your password without submiting and manually submit. This allows to support more websites.
+
 
 Technical details
 -----------------