tdf#83523 ruler: Invalidate full ruler rect on app bg change
Instead of waiting for the application to restart,
hack out an immediate invalidation of the ruler.
Perhaps there is a better place to do this
because the ruler background apparently IS
changing, but it seems to require a hack
to invalidate everything.
Change-Id: I4a27cbaf484e96c19c71c04017c649e95bf80d96
Reviewed-on: https://gerrit.libreoffice.org/c/core/+/128733
Tested-by: Jenkins
Reviewed-by: Justin Luth <jluth@mail.com>
Reviewed-by: Miklos Vajna <vmiklos@collabora.com>