[Solved] STEP file doesn't show in view area

Hello everyone,
Got problems with showing STEP file.
This code show only show black rectangle.

        reader.TransferRoots();
        TopoDS_Shape shape = reader.OneShape();

        // Create a new context and view
        Handle(AIS_InteractiveContext) newContext = new AIS_InteractiveContext(SharedViewer::getViewer());//just class for storing static Handle(V3d_Viewer) viewer;
        Handle(V3d_View) newView = SharedViewer::getViewer()->CreateView();
        Handle(OcctWindow) customWindow = new OcctWindow(newTab);
        newView->SetWindow(customWindow);

        if (!customWindow->IsMapped())
        {
            customWindow->Map();
        }
        Handle(AIS_Shape) aisShape = new AIS_Shape(shape);
        newContext->Display(aisShape, AIS_Shaded, 0, false);
        newView->FitAll();
        newView->Redraw();

for OcctWindow implementation i used this example from openCASCADE
And somebody could explain pls this implementation of View, moment about inheriting AIS_ViewController. Because in tools folder with plugins, they don't use such implementation. Same for FreeCAD source code(mb need further investigation).
Could provide any additional information if needed.
Thx in advance.

UPD: Fixed there was a problem with initialization of local variables for view, which further destroys.