Reference lines are wonderful. If done well, they can add so much context at a glance with very little effort to include them in your viz. However, reference lines in Tableau always sit on top of the rest of the viz. We may not want them to be so prominent though.
Wouldn't it be great if we could place them behind the bar, kind of like how you can decide which objects to move backwards on a PowerPoint slide?
First, let's build a simple bar chart of Sales with a reference line for Budget Sales.
If we click on one of the reference lines and then right-click, we don't have an option to move the marks to the back.
There's a super simple trick to move the reference lines to the back...Gantt bars!