I sometimes use dummy binder entries as markers. (Say for example, up to which point I’ve revised my story focusing on this or that thread, etc.)
It would be nice to be able to insert binder elements that don’t obey binder’s structure.
What I mean is that they could be moved up or down like normal binder elements, but without being stuck nested in a folder, or skipping over nested files.
In other words, that would freely move up one or down one (using the same shortcut as normal binder elements) no matter what.
And perhaps have them visually span all the way to the left. (No indent.) Something bolder than the current Show as Binder Separator.
Hmm, the thing is we thought about dividers, lines that you can add and drag up and down much like you describe, but didn’t like the idea of having something like that in the object list that is purely visual—it makes things a lot more complicated, like what happens if you Shift-Arrow through it, whether it selects at all and the amount of code it would take to build all of these exclusive behaviours. The Binder Separator approach was designed to directly address the desire for having major divisions and increasing visibility in longer lists, without introducing ornamental elements.
I understand what you are describing is different from that though, more of a sidebar “bookmark”, like how one might pin a line in a coding editor so that it can be returned to, placing a star or bookmark icon in the left gutter area.
It strikes me that icons would be a good way of handling that kind of “I am here” signal. Something bright and single in its purpose, like so:
Here is the icon and source file in case you like it as-is: