The code changes the users language for all the users who don't have the change own user language permission in a submit function. This causes problems when the number of users without that permission is high.
It would be better if the code would change the user language only for the currently logged in user.
Comments
Comment #1
avpadernoThis has been fixed in CVS for the Drupal 6 branch. The code must be changed for the Drupal 7 branch as well.
Comment #2
avpadernoIt has been fixed in the Drupal 7 branch too.