Time switcher doesn't work

In the default desktop switching the time format from 24 hours to AM/PM doesn't work in the "Time & Date settings..." when you click on the time in the panel. Neither from AM/PM to 24-hour (according to c107 in IRC) nor from 24-hour to AM/PM.

The only way to switch the format for me was to set in System settings -> Language Support in the tab Regional Formats to the "Display numbers, dates and currenty ammounts" to English (United States).

I guess the time applet uses the "Display numbers, dates and currency settings" rather than the Time & Date settings.