The ToX exists only once in the model, so it either has to have the
content corresponding to redlines being shown, or hidden.

Adapt Update based on current layout setting.

Change-Id: Ibf5ec092632cf3a5f513965afdb840fd8239a7fd
Reviewed-on: https://gerrit.libreoffice.org/65527
Tested-by: Jenkins
Reviewed-by: Michael Stahl <Michael.Stahl@cib.de>