Binder keyboard navigation; dragging from it across left editor outline; et al.

In the Binder, if I type the first character of a displayed item (folder or document) below the currently selected item, Scrivener seems to know my intent–to jump to that first-character’s next item.
But the visible selection does not jump thence, does not seem to jump at all. However, if I then down-arrow, the selection does jump, from the pre-type selection to the item just below my intended target (despite its having a different initial character). Or if I up-arrow, the selection goes to the item just above my target.
Interestingly … If my target is a folder and I right-arrow after my character typing, the target folder opens but still nothing is selected. (If I now down-arrow, the selection jumps to the folder’s first document–nice, were that my intent.
(If my target is a document, left- and up-arrows jump the earlier selection to the item immediately above the target, down-arrow, the item below; right-arrow, nothing.)

Alt-dragging a document from the Binder across an outline-mode left editor for the purpose of creating a link in a right editor document, the outline scrolls rightward (when the outline is not opened full width and the drag is not quick).

When I move the mouse pointer across the boundary between the binder or inspector and an editor window, even without turning ‘double-arrow’, the pointer (arrow) can grab the boundary and shift it, changing the widths of the two.

(Just an observation about nomenclature: There is a key combo labeled “Previous Collection” and another, “Next Collection”; It seems that by ‘previous’ we mean what I might call the next collection down the tab list; by ‘next’, the next collection up the tab list?)