First, thank you for keeping this essential module alive. It really is the one reason I use Xposed at all.
With that, though, I need to report a bug:
Since 2.0.6, Russian comes up as a "ru" locale. This does not, however, appear to work: Applications configured in 2.0.5 or earlier as "ru_RU" continue working in the locale specified. Setting the locale for a new application as "ru" does not appear to result in locale changing at all.
Rolling back to 2.0.5 fixes the problem.
I'm not sure whether it should work like that -- it seems to me that it's possible to translate an application into "ru_RU" but not "ru", so the fault might be with the developers of the specific applications I tried to change the locale on -- but the solution seems obvious: Make sure that both "ru" and "ru_RU" are available as selectable languages and let the user pick which one works in which particular case.