I find the document outline in Rstudio particularly helpful when working with Xaringan presentations, especially when I have a lot of slides. However, I have many slides that do not have titles (i.e., do not have a header), which causes them to not show up in the document outline. As a workaround, I have used titles/headers with transparent font but that takes up real estate on the slide even though the text is not visible. There must be a better approach. Any thoughts as to how I might make sure all slides in my presentation are included in the document outline even if they do not have titles/headers?