fixed bug in localization finder

Fixed bug for localization finder, when it has to look in another localization tree than the first one

- [x] test coverage
- [x] finish the code
- [x] gather feedback for my changes


| Q             | A
| ------------- | ---
| Bug fix?      | yes
| New feature?  | no
| Tests pass?   | yes
| Fixed tickets | #79
| Doc           | none