Note: this project was added previously as a maven dependency, so now we need to add it as a sources.
Project Structure -> Modules -> [+] -> Import Module
go through the wizard…
After that go to maven tab, then select grey root nodes, right click, choose ‘Unignore Projects’
Maybe you need to reopen IDE.
UPD: also you need to reload cashes. I did it by:
- change version of the adding library to one of previous
- click ‘Import Changes’ on the ‘Maven projects need to be imported’ tooltip
- change it back
- again click ‘Import Changes’ on the ‘Maven projects need to be imported’ tooltip