The folded column arrives whole, and the top edge is a title bar

Brought out at the edge after ⌘S (or unfolded again), the column slid
in while the traffic lights and the pinned tabs were already in place
over it. The lights were shown at once: they now ride in and out on
the column's own spring, a Core Animation copy of Motion.glide on the
title bar's layer, turning round from wherever they are. The pins sat
in a LazyVGrid, whose cells are made once the column is on screen,
out of reach of its slide: PinGrid lays the dozen squares out in full.

In the column's mode the page reaches the window's top edge, and
folded there was nowhere left to drag the window from or double-click
it. An 8-point DragStrip along the top stands in for the title bar,
under the column when it is out.

Checked on a hidden probe with ./bench: filmed, the pins now come in
with the column (before, they were in place from the first frame);
the lights end shown or hidden as they should through fold, peek and
quick back-and-forths, at their usual spots; hit reports the strip in
the top 8 points, folded or not, the page below it, and a double-click
there takes a 1200x800 window to the whole screen. Strip mode keeps
its own strip.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>