Remove visual noise from fpicker

Change-Id: I58ae70cc71853e17e638ef64aaded87615e37986
Reviewed-on: https://gerrit.libreoffice.org/8264
Reviewed-by: Caolán McNamara <caolanm@redhat.com>
Tested-by: Caolán McNamara <caolanm@redhat.com>