<zk>
    Please press on the two buttons twice, and then the scroll bar should be placed as the position as the selected item (blue background).
    <tree id="tree" width="400px" rows="3">
        <treecols sizable="true">
            <treecol label="Name" />
            <treecol label="Description" />
        </treecols>
        <treechildren id="t">
            <treeitem>
                <treerow>
                    <treecell label="Item 1" />
                    <treecell label="Item 1 description" />
                </treerow>
            </treeitem>
            <treeitem>
                <treerow>
                    <treecell label="Item 2" />
                    <treecell label="Item 2 description" />
                </treerow>
                <treechildren>
                    <treeitem>
                        <treerow>
                            <treecell label="Item 2.1" />
                        </treerow>
                        <treechildren>
                            <treeitem>
                                <treerow>
                                    <treecell label="Item 2.1.1" />
                                </treerow>
                            </treeitem>
                            <treeitem>
                                <treerow>
                                    <treecell label="Item 2.1.2" />
                                </treerow>
                            </treeitem>
                        </treechildren>
                    </treeitem>
                    <treeitem>
                        <treerow>
                            <treecell label="Item 2.2" />
                        </treerow>
                        <treechildren id="tc">
                            <treeitem>
                                <treerow>
                                    <treecell label="Item 2.2.1" />
                                </treerow>
                            </treeitem>
                        </treechildren>
                    </treeitem>
                </treechildren>
            </treeitem>
            <treeitem label="Item 3" />
        </treechildren>
    </tree>
    <button label="add under bottom">
        <attribute name="onClick">
            Treeitem ti = new Treeitem();
Treerow tr = new Treerow();
tr.appendChild(new Treecell("test"));
ti.appendChild(tr);
tc.appendChild(ti);
ti.setSelected(true);
        </attribute>
    </button>
    <button label="add upon top">
        <attribute name="onClick">
            Treeitem ti = new Treeitem();
Treerow tr = new Treerow();
tr.appendChild(new Treecell("test"));
ti.appendChild(tr);
t.insertBefore(ti, t.firstChild);
ti.setSelected(true);
        </attribute>
    </button>
</zk>