Selecting thumbs or flipping SINGLE <-> ALL THUMBS on a roll whose captions wrap
to different heights crashed the shelf with React #185 ("Maximum update depth
exceeded") and left the screen blank. useWallWindow read the step from one row to
the next off the rows the window itself had drawn, and the average of a run of
rows moves as the run grows: `to` traded places with a sum a row away — 35, 40,
35, 40, three milliseconds apart — every pass a render, until React gave up.
The step is taken once per column count and kept, re-read when the wall
re-columns, which is the only thing that changes a card own height (a caption
wraps at the width it is given). The window is a function of the scroll and
nothing else, so it settles.
Reproduced with the storm probe against a 3000-frame roll of unevenly named
frames: before, blank at round 1 with #185; after, 12 rounds of hard
SINGLE/ALL THUMBS toggling plus a round trip through the studio — no error, no
blank screen, and D18 unchanged (tile CHANGED, the shelf raising the studio
frame 4px off centre, the studio link opening the same frame).
3dtours
fc3f46c302