Scrollbars in a filtered TreeTable

Originally by whahn

This may be related to https://github.com/vaadin/framework/issues/2087.

If a filter filters out everything from a TreeTable, the currently visible scrollbar stays. If the same is done with an ordinary Table, the scrollbar vanishes as expected.

Sample code:

package test;

import com.vaadin.annotations.Title;
import com.vaadin.data.Container.Filter;
import com.vaadin.data.Item;
import com.vaadin.data.util.IndexedContainer;
import com.vaadin.server.VaadinRequest;
import com.vaadin.ui.Button;
import com.vaadin.ui.Button.ClickEvent;
import com.vaadin.ui.TreeTable;
import com.vaadin.ui.UI;
import com.vaadin.ui.VerticalLayout;

@Title("blargh")
public class TestUI extends UI {

    @Override
    protected void init(VaadinRequest request) {
        VerticalLayout mainLayout = new VerticalLayout();
        mainLayout.setWidth("800px");
        mainLayout.setHeight("450px");

        final IndexedContainer container = new IndexedContainer();
        container.addContainerProperty("asdf", Integer.class, null);
        for (int i = 0; i < 100; i++) {
            Item item = container.addItem(i);
            item.getItemProperty("asdf").setValue(i);
        }

        TreeTable tt = new TreeTable(null, container);
       _ Table tt = new Table(null, container); _ all is well

        tt.setSizeFull();

        Button b = new Button("filter everything");
        b.addClickListener(new Button.ClickListener() {
            @Override
            public void buttonClick(ClickEvent event) {
                container.addContainerFilter(
                        new Compare.Equal("asdf", "never matches"));
            }
        });
        mainLayout.addComponents(b, tt);
        mainLayout.setExpandRatio(tt, 1);

        setContent(mainLayout);
    }

}

Imported from https://dev.vaadin.com/ issue #14036

Start with the supplied TreeTable sample and compare its filtering behavior with the ordinary Table using IndexedContainer. Trace how TreeTable handles an empty filtered container and updates its visible scrollbar. Done means the scrollbar disappears after the filter removes every item, matching Table behavior.