6.99.44 — drop shading, a full arrangement, and deep links into the tree

Follow-ups to the category arrangement in 6.99.43.

Dragging

The shading says how far a drop reaches. Aiming at the middle of a row
shaded the row and everything under it, including the part of the tree a
collapsed category hides — more than the drop would touch. It now shades only
what the drop will actually reach.

A full arrangement says so. There is a limit on how many categories the
order can remember. Past it, a drag used to look like it had simply done
nothing: the row went back where it came from with no explanation. It now says
the arrangement is full.

Opening a link to a note

A link to a note filed deep in the tree opens the note. Following one
landed on the note, but the tree stayed as it was, so the note being read sat
inside categories that looked closed. The tree now opens far enough to show it
— only as far as that, and the collapse you made elsewhere is left alone and
not written over.