GXT how to implement window with proper layout for content

Window is ContentPanel
setLayout( new FitLayout )
add( LayoutContainer )
        VBoxLayout layout = new VBoxLayout();
layout.setPadding(new Padding(5));
layout.setVBoxLayoutAlign(VBoxLayout.VBoxLayoutAlign.LEFT);
layout.setPack(BoxLayout.BoxLayoutPack.START);

(LayoutContainer).setLayout(layout);
        add( button )
        add( safeHtmlText )

window.layout();