This issue is somehow quite similar to my last one about autocomplete in custom packages.
Now, my current issue is, that even though that the TestEnvironment runs perfectly, exporting always fails, because of references to other packages in classes that are from my package.
This includes both imports, accessing classes by the whole path, etc..
The console states "cannot find symbol" and points to the line, where the reference has been used. Removing the reference from the class, that the compiler stated just makes it find another case of this issue.