Eclipse won't show Ceylon source files

I have created a Ceylon project in Eclipse Oxygen. There are Ceylon source code files in the folder C:\Users\Jon\Aukitekt\milling\source\designs, but these are not shown inside Eclipse, as can be seen in this screenshot:

EDIT:

Making a single run, to 'kickstart' Eclipse, seems not possible. In run configuration I cannot click 'Run', for some reason.

Refreshing the Project Structure Window (right click -> refresh) revealed two files in the root:

• ceylonb

• ceylonb.bat

  but no files in the source directory was revealed.

  The problem might boil down to Eclipse not recognizing this as a proper Ceylon project, as suggested by Vitaly Banchenko.

The problem was that the project was not created as a proper Ceylon project.

When creating the project, choose

File -> New -> Ceylon project

rather than

File -> New -> Project