Resolves: tdf#130756 null deref in empty treeview

Change-Id: Ie43081d5c1feb655ea1479476375ee7381f0a0ef
Reviewed-on: https://gerrit.libreoffice.org/c/core/+/88934
Tested-by: Jenkins
Reviewed-by: Caolán McNamara <caolanm@redhat.com>
diff --git a/vcl/source/app/salvtables.cxx b/vcl/source/app/salvtables.cxx
index 5b2a288..d04ccbf 100644
--- a/vcl/source/app/salvtables.cxx
+++ b/vcl/source/app/salvtables.cxx
@@ -6466,7 +6466,10 @@ IMPL_LINK(SalInstanceEntryTreeView, KeyPressListener, VclWindowEvent&, rEvent, v
        m_pTreeView->disable_notify_events();
        auto& rListBox = m_pTreeView->getTreeView();
        if (!rListBox.FirstSelected())
            rListBox.Select(rListBox.First(), true);
        {
            if (SvTreeListEntry* pEntry = rListBox.First())
                rListBox.Select(pEntry, true);
        }
        else
            rListBox.KeyInput(rKeyEvent);
        m_xEntry->set_text(m_xTreeView->get_selected_text());