Glad that it did help! As a result of this topic discussion I've created KT-1612 to prevent appearing this problem in future.
I expect that your current problem will dissappear after moving kotlin file into src folder (I saw from your last screenshot that Hello.kt is under module folder). I expect that there’s should be some warning about this situation too.
Oops, I didn't notice that my source was not in the src/ directory. Moving it there did fix the problem, thanks!
Feature request: either support source files outside of src/ (“Are you sure you want to put your file there? This is not a source directory.”) or don’t allow stupid users such as myself to create them there 
Mind to file this in the tracker? Thanks