The commit 461e0f9e broke accessibility
on Mac. This patch tweeks two changes in the original commit and at
least removes the accessibility warnings about the wrong window being
reported as parent.

Change-Id: I0faa631d22376adc08a191ba5937363d1dee059e
Reviewed-on: https://gerrit.libreoffice.org/7837Reviewed-by: Miklos Vajna <vmiklos@collabora.co.uk>
Tested-by: Miklos Vajna <vmiklos@collabora.co.uk>