Didn't advance too much on the GUI restructuring.
Decided to replace the main Form with a WPF one, for now the WPF form is built in parallel with the current form. Succeeded also to integrate the Weifen Luo docking control on it. Evaluating if there is any point on keeping the docking control and windows or to replace them with WPF versions together with the main form.
After integrating all these elements the next step will be to map OpenCascade to render on the forms and also wire the toolbar events.