In the normal course of work, there is no marking of segments that are going to be repeated later on. Only later on, you might see a small red P in the repeated segment.
However, as a kind of base feature, it should be made clear in the first occurrence that a segment is going to be repeated.
Just to be clear: This marking can be a small dot or arrow.
SmartCat offers here a real nice thing – an arrow …
… that can be clicked on to avoid forward propagation.
Nice and cool.