Tab leaders are the lines of filler characters in printed lists and tables of contents that connect the aligned content on one side to the aligned content on the other, both leading the eye and filling in what would otherwise be an awkward trapped space.
To create tab leaders in InDesign, once the list is created, open the Tabs palette (Mac: CMD-SHIFT‑T, Win: CTRL-SHIFT‑T, or Menu: Window>Type & Tables>Tabs), and once your content is aligned, select the tab on the Tabs palette and place the desired tab leader character (or characters-up to 8 are allowed) in the “Leader:” box.
If the tab leaders get too dense, add a space (or two, as appropriate) after the tab leader character.
So, does anyone know a way to change the size of the leaders in the tab ruler without effecting the size of the type? Say you want to use periods, but make them smaller than the text, and you want to do this to multiple lines rather than selecting each line of periods separately?
An experiment I’m trying right now (inspired by your query) suggests that nested styles may hold a possible answer.
Using a quick, three-line (with forced line breaks) TOC, I styled the tab leader characters (after creating the tab leader-you of course cannot style the tab leader in the creation dialog), adjusting point size and leading as appropriate (just for fun, I blew up the full-stops and had to adjust the leading way down).
By styling the tab leaders and creating a paragraph style from that, I was able to incorporate that into a paragraph style. Of course, you’ll probably want to create and style each line of your list as a separate paragraph because I don’t know how to tell Indy to go back and loop through the nested style until you’re out of lines (if you use forced-line breaks as I did).