diff --git a/.hgtags b/.hgtags
index ea36fb4ca..ea6232dde 100644
--- a/.hgtags
+++ b/.hgtags
@@ -60,3 +60,4 @@ b0a3802767becc2ac4ed5c722dab81f78a253bd3 THUNDERBIRD_3_0_2_RELEASE
 308532e25a80adc8657c9fe4a9a6c50945ef333a FIREFOX_3_7a2_RELEASE
 2a640df3406de6d854ffb05e40e2f3750e78badd THUNDERBIRD_2_0_0_24_RELEASE
 7dee7e34f2e63f4565fd2beffdb91c7277cd0d38 FIREFOX_3_0_19_RELEASE
+833b5ba4f274c7e98d50ab3e01f2b501acd6a99a FIREFOX_3_5_9_BUILD1