I often have multiple tiers open in my binder. It might looked like Research–>Places–>City X–>So and So’s house. Let’s say I’m done referencing this particular place and need to look at a character (Research–>Characters–>So and So). I can just collapse it on the “Places” level and go over to “Characters” but next time I come to Places it opens up right where I left off. That’s helpful for moving back and forth, but once I’m finished with the whole subject, it would be nice to “collapse all” and start fresh. Just a thought.
This is already offered, in multiple levels of specificity:
- Collapse all within a single lineage by Alt-clicking on the disclosure triangle. That will expand or collapse the item and all descendants.
- Collapse or Expand the entire Binder from top to bottom with
View/Outline/Expand Alland.../Collapse All.
I am looking for this in the Windows version and just can’t find it. 
EDIT By chance I stumbled across the answer in a wholly unrelated thread… hold down the Alt key while clicking on the +/- for the highest level folder to either open or collapse. 
ALT-clicking on the disclosure triangles, as Ioa mentioned, works for me on the Windows version.
Also, if you didn’t see the Outline sub-menu under View, look lower; there are actually two entries for “Outline” under View.
Bingo! many thanks, sir. 
And by “triangles,” do you mean the little + / - box ?
Yes; this is just a difference of the different Windows operating systems. On XP they appear as the + and - boxes; on everything newer they’re triangles (unless Win8 went off and did something else; I haven’t checked).
Very well put! (re: Win8) 
Thanks!