Resolves: tdf#137703 crash on 2nd launch of cell bg color dropdown

Change-Id: I263edf36d70b3b81051c7aa5ca44523d0193975f
Reviewed-on: https://gerrit.libreoffice.org/c/core/+/104719
Tested-by: Jenkins
Reviewed-by: Caolán McNamara <caolanm@redhat.com>
diff --git a/svtools/source/control/toolbarmenu.cxx b/svtools/source/control/toolbarmenu.cxx
index 259115c..b376490 100644
--- a/svtools/source/control/toolbarmenu.cxx
+++ b/svtools/source/control/toolbarmenu.cxx
@@ -218,6 +218,7 @@ void InterimToolbarPopup::dispose()
    m_xContainer->move(m_xPopup->getContainer(), m_xPopup->getTopLevel());
    m_xPopup.reset();
    m_xContainer.reset();
    m_xBuilder.reset();
    m_xBox.clear();
    m_xFrame.clear();
    DockingWindow::dispose();