Sources are not attached to all jars in multi-module projects

[Gert Palok]

1. Create module_a
2. Add dependency_a to module_a
3. Create module_b
4. Add dependency_a to module_b
5. Click find sources for dependency_a

Result: dependency_a gets source attachment only in module_a

Expected: dependency_a gets source attachment in module_a and module_b