the reason is ubuntu changes the user string to omit the Gecko/$build_date part of the useragent string.
I found this note in the changelog for1.5.dfsg+1.5.0.4-1ubuntu1, under the 'differences between ubuntu and debain' part of the changelog: "Less detail in the user agent string" Changing the useragent string to include Gecko/00000000 lets gmail work correctly again (defualt useragent can be overridden by adding the general.useragent.override pref). -- latest firefox update breaks gmail https://launchpad.net/bugs/52373 -- ubuntu-bugs mailing list [email protected] https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
