diff --git a/doc/sandbox.mdwn b/doc/sandbox.mdwn
index 9291681d3..2f95d4791 100644
--- a/doc/sandbox.mdwn
+++ b/doc/sandbox.mdwn
@@ -16,6 +16,8 @@ OpenID test. It works!!
 
 Test..
 
+There are Polish diacritical characters: ą, ć, ę, ł, ń, ó, ś, ż, ź.
+
 # Header
 
 ## Subheader