This provide the correct invalidation and drawing of the combo box
control which is used for cell where a validation list has been set
up.

This patch fixes also tunneling issue for the floating window showing
the list of valid entries.

Change-Id: I9f7277688293eff443504221c7c7e46097a5da4a
Reviewed-on: https://gerrit.libreoffice.org/50893Tested-by: Jenkins <ci@libreoffice.org>
Reviewed-by: Marco Cecchetti <mrcekets@gmail.com>