To help client know when the user has selected a non-null text.

Change-Id: Ie939612fc5f38e2e50e9ad9792e04e89ae918886
Reviewed-on: https://gerrit.libreoffice.org/20621Tested-by: Jenkins <ci@libreoffice.org>
Reviewed-by: Miklos Vajna <vmiklos@collabora.co.uk>