My app supports only 2 languages - English and German. So I have such folders structure for languages strings:
myproject/res/values/strings.xml my
myproject/res/values/strings.xml
my
Same issue here.
I created a bug report, feel free to star it
http://code.google.com/p/android/issues/detail?id=50525
This happened since ADT 21.1 release.
I know no workaround for it (editing: I previously though to have found a workaround, but I looked at the wrong file, ups)