fdo#73869 fix highlight RTL Problem at the StartCenter window.

Change-Id: I2fb5bf97941478781c0a77b55d4454acd00f903b
Reviewed-on: https://gerrit.libreoffice.org/8199
Reviewed-by: Caolán McNamara <caolanm@redhat.com>
Tested-by: Caolán McNamara <caolanm@redhat.com>