Thank you @Mike53 and @Puybaret, that was exactly what I was looking for!

Thank you for your kind reply.
User's guide helped me with assigning different colours to walls (inside/outside). But I'm still not able to address a different colour to the inside part of the frame of the window.

Any help?

Hi all,

how can I manage to address a different colour on the inside and on the outside of my windows?

Greetings
robsen33