Code generation not working for one or several classes

The project file in Visual Studio should have dependencies defined.

<Compile Include="EcoProject1\Class1.cs" />
   <Compile Include="EcoProject1\Class1.eco.cs">
     <DependentUpon>Class1.cs</DependentUpon>

</Compile>

If this structure isn't correct, for example due to a merge error in source control, do this to correct it.

1. Exclude (not delete!) all the generated class code files, both the .cs and the .eco.cs files.
2. Code generate everything again with "Ctrl + <the C# button>"

No files will be overwritten but the correct VS structure will be regenerated.