Split off from http://forums.asp.net/t/1646509.aspx/1?Losing+current+culture+with+ajax#.
I have the same exact problem as the OP and it doesn't look like anyone answered his question probably because they didn't understand.
I have a page with a user control. In the page I override the InitializeCulture method to set the CurrentCulture and CurrentUICulture to the one the user wants.
The user control works and when I check the current culture it's set correctly however when there is ajax involved and the user control does a ajax call back the currentthread culture is lost and set back to the machine not the one I set in the page load.
Is ajax launching a seperate thread for the callback which would explain the lost culture or is there another problem. IT seems the only work around would be for every user control overrise the InitializeCulture method in it along with in the page.