I\'ve created a play project with play 2.3.7
In the project directory, I ran activator and ran the eclipse
command to generate eclipse project files.
I tried all solutions without any positiv result.
So I went to Preferences > Build, Execution, Deployment > Build Tools > sbt
and checked Use sbt shell
for imports and builds.
This let the compile button in intelliJ compile with the sbt shell.
I think this is better anyway, since a build server or something similar will compile the same way and not like intelliJ.