Eclipse uses wrong build configuration

Question

I do have a strange problem about build-configurations.

I do have three projects, say A, B and C. A is a library and B and C are referencing it.

In the project properties under 'C/C++ General' -> 'Paths and Symbols' in the tab 'References' I can select the project A and I do have the option to select '[Active]', 'Debug' or 'Release'.

I did intentionally select 'Debug' or 'Release' depending on the build configuration of projects B and C and did un-check '[Active]'.

Now I select 'Debug' as the build configuration for A and 'Release' for B and C (for test purpose). I expected that eclipse would build A depending on my build configuration, but it always builds the active one (i.e. 'Debug').

Do I have to configure something else?

Thanks, Johann

PS: I do use CMake and alternative build commands, which I already checked.