Set focus to the clicked panel title

Change-Id: I65993a6a2f8e7a9a2bdaa6cf4527d5b163d81409
Reviewed-on: https://gerrit.libreoffice.org/59694
Tested-by: Jenkins
Reviewed-by: Caolán McNamara <caolanm@redhat.com>
Tested-by: Caolán McNamara <caolanm@redhat.com>