I've tested Firefox 41 on Ubuntu 15.04 and I'd say that the issue has been fixed. Here is the test procedure:
(1) Check your Regional Formats in System Settings > Language > Language Support > Regional Formats. Let's say this option is set to "English (United Kingdom)" (if you change it, the change takes effect the next time you log in). That option will change the environment variables for various locale categories including LC_PAPER.
(2) Start Firefox with default user settings. You can do it by running "firefox -P" and creating a new user profile.
(3) Try to print (Ctrl+P). On the Page Setup tab you get "Paper size: A4".
I get this result even without step (2).
If the Regional Formats are set to "English (United States)" then you get "Paper Size: US Letter".
You can also test this without changing Regional Formats: in the Terminal Window run the following commands and check the paper size as in step (3) above:
I've tested Firefox 41 on Ubuntu 15.04 and I'd say that the issue has been fixed. Here is the test procedure:
(1) Check your Regional Formats in System Settings > Language > Language Support > Regional Formats. Let's say this option is set to "English (United Kingdom)" (if you change it, the change takes effect the next time you log in). That option will change the environment variables for various locale categories including LC_PAPER.
(2) Start Firefox with default user settings. You can do it by running "firefox -P" and creating a new user profile.
(3) Try to print (Ctrl+P). On the Page Setup tab you get "Paper size: A4".
I get this result even without step (2).
If the Regional Formats are set to "English (United States)" then you get "Paper Size: US Letter".
You can also test this without changing Regional Formats: in the Terminal Window run the following commands and check the paper size as in step (3) above:
LC_PAPER= en_GB.UTF- 8 firefox
LC_PAPER= en_US.UTF- 8 firefox