Vertical lines exist at a single rhythmic position and are positioned relative to notes, chords or rests at that position.
But you can’t put a line against a solo rest, so that is somewhat misleading, in a way.
Here’s a thread with a lot of workarounds for this limitation, and a request to make it possible.
Before I tag this with a feature request tag, is it in the worklist for feature requests?
[On a related note it would be good if we forum users making feature requests could perhaps access a page showing the list so as to avoid duplication etc. I suppose that’s a Steinberg feature request ]
I doubt it’s as binary as that. Daniel’s recent statements seem to suggest there are perhaps many hundreds of items on their ‘possible developments’ list. I doubt any suggestion is rejected out of hand.