If you resize the rows to at least double their default size and if the
model specifies a scale it will be drawn as additional horizontal lines
and numbers in the background.

Change-Id: I02844b4102e043031ee04daa45666dc3f8da1d2e
Task-number: QTCREATORBUG-12337
Reviewed-by: Kai Koehne <kai.koehne@digia.com>