Please allow double-click to drill down in the binder.
At the moment this triggers Rename. I don’t rename nearly as often as I unfold.
For Renaming, pressing F2 works already. Scrivener is more compliant with Windows conventions here.
Throughout the Windows world, dbl-clicking in a tree structure drills down, whether it’s image viewers or outliners or file managers. Even Win Explorer itself behaves in this way. It has become second nature, because it gets reinforced all the time.
Whenever you come across a tree structure in the Windows world, you dbl-click items and they unfold. No need to aim at tiny arrows, on the border of the screen, way out left, precariously close to my second monitor on the left, where I end up accidentally.
So please, make the fold/unfold action an optional behavior in Options > Behavior.
It’s not so much that the arrow is so hard to see that user can’t tell whether the binder item has children or not, it’s more that the arrow is so hard to see so the user can’t click on it accurately enough to reveal the children.
I believe this is standard out-of-the-box Dark Mode, using this as an example just because it’s the theme I happen to have on at the moment:
While it’s not impossible to see the arrow of the selected item, it’s certainly easier to see the non-selected ones. Probably 85+% of the time I’ll hit the arrow when I try, but occasionally I do miss.
As stated in the OP –
So why not make it standard in the Scrivener binder?
But the biggest justification for changing the Binder to this standard is because that’s how the Outliner works. Double-clicking the Outliner icon (not the name) of a parent item will drill down to the children. Why shouldn’t the binder work the same way?
(To be honest, it was just during writing this post that I realized that’s how the Outliner works. In all these years 'd never tried double-clicking the Outliner to drill down, because the Binder doesn’t support it. They should be consistent, so that sure seems like an oversight.)
How hard it is to aim at the unfold-icons, depends on the theme and screen resolution, on your pointing device (trackpad vs mouse etc), whether you have another monitor sitting left of the binder, …
To avoid misunderstandings: I did NOT mean to force everybody else to abandon their preferences. What I asked for, is to make it available as an optional behavior. So I will not be forced either to change my ingrained Windows habits.
Personally, I find it much more user-friendly — on all tree lists, not just Scriv — to point at a larger area, then sweep down vertically to open/close other nodes, without having to reposition the mouse horizontally for every indent level.