With the sidebar open the native window controls live in the sidebar, so the compact
bar only needs its own 16px inset. Collapsing the sidebar moves those controls above
the page, and the compact bar then adds the frame's top clearance so its controls stay
below them instead of underneath.
The style-driven motion between the expanded and compact bars still needs work; it lands
in a follow-up.
The page carried a 28px top inset above its head row, so the window's topmost 28px on that page belonged to no drag region — the frame's former band covered it, and the per-row mark did not. The inset moves into the head rows themselves (.pageHead and .detailTop), which now start at the window's top edge while the content keeps its position. The browser lane pins each row's top edge at zero and the negative control confirms both assertions fail on the pre-fix sheet.
The macOS window's draggable area was a hand-written band: a 52px strip, deepened
to 76px by a marker the Conversation header had to keep in step with its own
height. It drifted from the layout — blank runs inside a chrome row did not drag,
and a control a few pixels away dragged the window instead.
Chrome rows now mark their own element (`data-window-drag`) and the shell declares
the surface once (`html[data-platform='darwin'] [data-window-drag]`), so a row's own
box is its draggable geometry and no fixed band has to match any row's height. The
frame band, its 52/76 figures, the marker, and the per-sheet drag rules are gone;
interactive controls and overlays portal beside `#root` where one rule subtracts
them.
Recollection becomes one shell watcher (`window-drag/recall.ts`): Electron rebuilds
the window's drag rects only when a computed app-region value changes
(electron#32341), so the watcher measures every marked row each frame while the
surface moves, sets `data-window-drag-recall` for the frames whose geometry changed,
and clears it on the frame that finds the geometry settled. The right panel's
hand-written pulse is deleted with it.
Coverage is a contract with executable parts. `window-drag/regions.ts` publishes the
composition rule and the interactive selector that both the sheet and its spec
compare against; the ui-theme gate asserts the package tree declares drag in exactly
two places and pairs every row's mark with its sheet, selector, and authored height;
and the browser lane boots the shipped composition in Chromium with the darwin
marker to assert per-row geometry, a content body under a marked head row, a
covering overlay, and the watcher's pulse. The plugin manager's detail views mark
the head row they share rather than the pane they render in, so their text and form
labels stay content.
Both real machines agree: the macOS matrix ran on a real `hiddenInset` window with
HID-level pointer input and window-frame readback, and the Windows matrix on a
Windows 11 ARM64 VM — chrome rows drag, content and the covering overlay do not,
and the controls keep their clicks.
Refs #4619
imccyu