VerticalSplitPanel hides grid's caption

Vaadin Framework version:

8.8.2

Browser version:

Chrome latest

Web container name and version:

embedded jetty

Description of the bug:

If you place a grid with a defined caption inside a VerticalSplitPanel, the caption will not be shown.

Minimal reproducible example

@Theme("mytheme")
public class MyUI extends UI {

    @Override
    protected void init(VaadinRequest vaadinRequest) {
        final VerticalSplitPanel layout = new VerticalSplitPanel();
//        final VerticalLayout layout = new VerticalLayout();
        
        Grid<String> grid = new Grid<>("Grid Caption");
        grid.addColumn(item->"Column Value 1").setId("column1");
        grid.addColumn(item->"Column Value 2").setCaption("Column 2");
        grid.addColumn(item->"Column Value 3").setCaption("Column 3");
        grid.setItems("Item 1","Item 2","Item 3","Item 4","Item 5","Item 6","Item 7","Item 8");
        layout.addComponents(grid);
        
        setContent(layout);
    }

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

Expected behavior

It should show grid's caption.

Actual behavior

It's not showing grid's caption. If you replace the layout for a VerticalLayout (uncomment line in the provided example, and comment the VerticalSplitPanel instantiation) then the caption will be shown.

Start with the supplied Java minimal reproducible example, using VerticalSplitPanel and then VerticalLayout for comparison. Confirm the grid caption behavior in both layouts, then trace the VerticalSplitPanel rendering path; done means the grid caption is visible when placed inside it without changing the grid configuration.