Composite with VerticalLayout root breaks layouting

[tepi]

Tested on Vaadin 8.11.3 and MacOS Chrome Version 87.0.4280.67 (Official Build) (x86_64). Also occurs in Firefox, so does not seem to be browser-dependent.

Problem: LayoutManager does not seem to properly recalculate sizes for various components which are in a Composite that has a VerticalLayout as its root. So in the first example the connector hierarchy is Composite->VerticalLayout->Grid.

public class MyUI extends UI {

	@Override
	protected void init(VaadinRequest vaadinRequest) {
		CompositeGrid vsp = new CompositeGrid();
		setContent(vsp);
	}

	@WebServlet(urlPatterns = "/*", name = "MyUIServlet", asyncSupported = true)
	@VaadinServletConfiguration(ui = MyUI.class, productionMode = false)
	public static class MyUIServlet extends VaadinServlet {
	}

	private Component buildGrid() {
		Grid<Person> grid = new Grid<Person>(Person.class);
		grid.setSizeFull();
		List<Person> persons = new ArrayList<>();
		for (int i = 0; i < 100; i++) {
			persons.add(new Person("Firstname" + i, "Lastname" + i));
		}
		grid.setItems(persons);
		return grid;
	}

	public class CompositeGrid extends Composite {
		public CompositeGrid() {
			VerticalLayout root = new VerticalLayout();
			root.setMargin(false);
			root.addComponentsAndExpand(buildGrid());
			setCompositionRoot(root);
			setSizeFull();
		}
	}
}

This does not seem to depend on Grid, also happen on SplitPanel in same kind of hierarchy:

public class MyUI extends UI {

	@Override
	protected void init(VaadinRequest vaadinRequest) {
		CompositeVSP vsp = new CompositeVSP();
		setContent(vsp);

		CompositeHSP hsp = new CompositeHSP();
		hsp.setSizeFull();
		vsp.set2(hsp);
	}

	@WebServlet(urlPatterns = "/*", name = "MyUIServlet", asyncSupported = true)
	@VaadinServletConfiguration(ui = MyUI.class, productionMode = false)
	public static class MyUIServlet extends VaadinServlet {
	}

	public class CompositeVSP extends Composite {

		private VerticalSplitPanel verticalSplitPanel;

		public CompositeVSP() {
			verticalSplitPanel = new VerticalSplitPanel();

			VerticalLayout root = new VerticalLayout();
			root.setMargin(false);
			root.addComponentsAndExpand(verticalSplitPanel);
			setCompositionRoot(root);
			setSizeFull();
		}

		public void set1(Component c) {
			verticalSplitPanel.setFirstComponent(c);
		}

		public void set2(Component c) {
			verticalSplitPanel.setSecondComponent(c);
		}
	}

	public class CompositeHSP extends Composite {

		private HorizontalSplitPanel horizontalSplitPanel;

		public CompositeHSP() {
			horizontalSplitPanel = new HorizontalSplitPanel();
			VerticalLayout root = new VerticalLayout();
			root.setMargin(false);
			root.addComponentsAndExpand(horizontalSplitPanel);
			setCompositionRoot(root);
			setSizeFull();
		}

		public void set1(Component c) {
			horizontalSplitPanel.setFirstComponent(c);
		}

		public void set2(Component c) {
			horizontalSplitPanel.setSecondComponent(c);
		}
	}
}

So to me it looks like when you have a Composite with a VerticalLayout as its root, any ManagedLayout implementors in that VerticalLayout fail to resize when they should.

[tepi]

Video of behavior: https://gofile.io/d/vK8TOH