Each unique package name causes the whole set of resource fields to be duplicated which can lead to the "Too many field references" error during compilation.
See this post for more information: https://www.b4x.com/android/forum/threads/preferences-material-design-preferences.75482/#post-479172
Note that you can also apply it to third party libraries if you compile them yourself. You will need to update the "import <package>.R" line.
This suggestion is not correct anymore. Please use a unique package name.