Finally I have found suitable GUI library. I have decided to use Dear ImGui library you can find it here.
I have integrated this library into my engine and I think looks much better than with pure WIN32 API. I think this was good decision as I do not have to spent too much time to add new gui controls like button or label or list or even creating new window. This library is very easy to use and I definitely recommend it to anyone. I still need to put much more work in the Editor Gui as is missing a lot of functionality, but I am very happy with the current result.
Currently you can manipulate all components, selecting and displaying components for specific game object in the scene through the Editor.
I have also added new Mesh Rendering component which handling 3D models. Still need to test it but for now the Engine is handling obj. and fbx models.